ORTHOPEDIC MCQS ONLINE 014 PATHOLOGY 

Musculoskeletal Tumors and Diseases Self-Assessment Examination AAOS

                    2014..by Dr.Dhahirortho            

 

 

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CLINICAL SITUATION FOR QUESTIONS 1 THROUGH 4

Figures 1a through 1c are the radiograph, CT scan, and bone scan of a 49-year-old woman admitted to the hospital with right hip pain and an inability to bear weight for 2 days. She states that the pain began 3 months ago, but suddenly progressed just before her admission.

 

 

 

 

Question 1..You decide to obtain further imaging. The best test to order would be

1. Ultrasound of the thyroid.

2. MRI scans of the pelvis.

3. CT scan of the chest, abdomen, and pelvis.

4. Indium-labeled bone scan.

 

Question 2..Given the scenario, what is the most likely finding on histopathologic review?

1. Metastatic adenocarcinoma

2. Ewing sarcoma

3. Lymphoma of bone

4. Hip joint sepsis

 

Question 3 ..The preferred surgical intervention for this fracture is

1. Radical resection and reconstruction

2. Intramedullary nail fixation

3. Cannulated screw fixation

4. Complex total hip arthroplasty

 

Question 4 ..External beam radiotherapy

1. should include the instrumented femur and periacetabular area.

2. should include the femur only.

3. should include the acetabulum only.

4. is contraindicated for this patient.

 

DISCUSSION…The occurrence of a femoral neck fracture in a relatively young patient with no history of trauma should alert the physician to potential for an underlying pathological process. The most likely culprit would be metastatic disease, myeloma, or lymphoma. Systemic imaging is undertaken to determine whether a primary site or site(s) of metastasis can be discovered. Only after obtaining tissue can the definitive diagnosis be made. Common primary malignancies that metastasize to bone are breast, lung, prostate, renal, and thyroid carcinomas. Multiple myeloma and lymphomas may also have a similar appearance in the bone. In this instance, not only is the femoral neck fractured, but there is a substantial lytic process in the acetabulum as well as other skeletal sites of involvement. Therefore, complex hip arthroplasty is the best choice for surgical intervention. Radiotherapy is indicated in the care of this patient as well. Generally, the radiation field should include the entirety of the involved implants plus a margin of tissue around them. In this case, this would include the entire progression of instrumented femur and the periacetabular area. This approach minimizes risk for local recurrence and transplanted tumor during instrumentation and/or as a result of postoperative ecchymosis or bleeding. There is no indication for preoperative radiation in this scenario.

PREFERRED RESPONSE 1..: 3- CT scan of the chest, abdomen, and pelvis. PREFERRED RESPONSE2…: 1- Metastatic adenocarcinoma

PREFERRED RESPONSE 3…: 4- Complex total hip arthroplasty

PREFERRED RESPONSE4 …: 1- should include the instrumented femur and periacetabular area.

 

Question 5 ..Li-Fraumeni syndrome (LFS) is associated with

1. multiple hemangiomas.

2. multiple hereditary osteochondromatosis.

3. soft-tissue sarcomas.

4. neurofibromatosis.

 

DISCUSSION…LFS is a rare genetic condition characterized by an increased risk for developing multiple types of cancer. The most common types of cancers associated with LFS include soft-tissue sarcomas (tumors in fat, muscle, nerves, joints, blood vessels, bones, or deep skin), breast cancer, leukemia, lung cancer, and brain tumors. The cancers that occur in LFS can be diagnosed during childhood, adolescence, or adulthood. Most people with LFS are found to have mutations in the TP53 gene. Multiple hemangiomas, osteochondromas, and neurofibromatosis are not associated with LFS. PREFERRED RESPONSE: 3- soft-tissue sarcomas.

 

Question 6 ..A 60-year-old woman has a proximal femur fracture. A permeative, lytic defect is recognized at the fracture site. Appropriate imaging studies are performed and show no other lesions. What is the next treatment step?

1. Cephalomedullary nail

2. Standard antegrade intramedullary nail

3. Resection and arthroplasty reconstruction

4. Open biopsy

 

DISCUSSION..In this patient, tissue diagnosis should be obtained prior to any surgical intervention to avoid unnecessary contamination in the event the lesion is a sarcoma. Open biopsy will yield the

 

diagnosis in the majority of cases. The specific choice for surgical treatment of a proximal femur pathologic fracture is controversial, but it would typically involve either a cephalomedullary nail or resection/reconstruction. A simple antegrade femoral nail rarely is sufficient in this setting.

 

 

PREFERRED RESPONSE: 4- Open biopsy

 

CLINICAL SITUATION FOR QUESTIONS 7 THROUGH 9

 

Question 7 ..What feature of the lesion most eliminates the need for biopsy prior to resection?

1. Painless nature

2. Location

3. Appearance on MRI scan

4. Rate of growth

 

Question 8 ..Atypical lipomatous lesions often appear as benign lipomas. What study will distinguish an atypical lipomatous lesion?

1. Cytogenetic testing showing evidence of a ring chromosome (MDM 2)

2. MRI scan showing an entire lesion made up of material isointense to fat on all sequences

3. Hematoxylin and eosin staining showing mature adipocytes

4. Immunohistochemistry staining for BCL-2

 

Question 9..The pathology is consistent with atypical lipomatous tumor (ALT) well-differentiated lipoma-like liposarcoma (WDLLS). What is the appropriate treatment and prognosis for this condition?

1. Wide excision with a high chance of local recurrence and moderate chance of metastasis

2. Marginal excision with a moderate chance of local recurrence and low chance of metastasis

3. Intralesional excision with a low chance of local recurrence and low chance of metastasis

4. Intralesional excision with a low chance of local recurrence and high chance of metastasis

 

DISCUSSION…ALTs are the extremity equivalent to a well-differentiated liposarcoma (WDLS) of the retroperitoneum and other visceral locations. ALTs can pose a difficult diagnostic dilemma.

They often appear as lipomas, characterized as being made up entirely of fat, isointense to fat on all MR scan sequences without heterogeneity. Atypical features may be increased thickened internal septation, large and deep nature, and enhancement on post-gadolinium studies. With no heterogeneous portions on MRI scan, biopsy is not needed because it is unlikely to differentiate lipoma from ALT. The painless nature or superficial locations are not reliable indicators of benign lesions. Concurrent surgery is never an appropriate reason for a lesion to be removed unless previous imaging shows otherwise.

Benign lipomas and ALT may have some similarities. They both appear on MRI scan to be made of fat with identical signal characteristics. Routine histology will show mature adipocytes in both with minimal atypia in the ALTs. Cytogenetic testing, however, will show a supernumerary ring and/or giant rod chromosomes in ALT, with amplification of the MDM2 oncogene. BCL-2 is the B-cell lymphoma apoptosis regulator protein, seen in lymphoma as well as some leukemias and carcinomas.

ALT or WDLLS are lesions with a moderate chance of local recurrence—certainly higher than for ordinary lipoma, with reported rates of up to 50%. They pose low, if any, distant metastatic potential. For this reason, marginal excision is recommended. When these lesions are locally recurrent, they most likely are of the same histology; however, a small percentage can return as a higher-grade malignancy (with an associated increase in metastatic potential). The other concern

 

regarding ALTs is the reported up to 10% incidence of dedifferentiation within them, underscoring the recommendation for excision.

PREFERRED RES 7..: 3- Appearance on MRI scan

PREFERRED RES 8..: 1- Cytogenetic testing showing evidence of a ring chromosome (MDM 2) PREFERRED RES 9…: 2- Marginal excision with a moderate chance of local recurrence and low chance of metastasis

 

RESPONSES FOR QUESTIONS 10 THROUGH 12

1. Wide resection alone

2. Amputation

3. Chemotherapy and external beam radiation

4. External beam radiation and surgical resection

Match the preferred treatment option above with the patient description below.

 

Question 10 ..A 70-year-old woman has a 15-cm subfascial soft-tissue sarcoma in her left thigh with no signs of metastatic disease on staging studies.

1. Wide resection alone

2. Amputation

3. Chemotherapy and external beam radiation

4. External beam radiation and surgical resection

 

Question 11..A 57-year-old woman has a 3-cm low-grade subcutaneous sarcoma of the upper arm.

1. Wide resection alone

2. Amputation

3. Chemotherapy and external beam radiation

4. External beam radiation and surgical resection

 

Question 12 ..A 33-year-old man has an unplanned resection of a high-grade pleomorphic sarcoma of the hand with multiple positive microscopic margins on final pathology.

1. Wide resection alone

2. Amputation

3. Chemotherapy and external beam radiation

4. External beam radiation and surgical resection

 

DISCUSSION..The management of soft-tissue sarcoma can present unique challenges. A systematic approach is necessary if undue complications and problems are to be avoided. In general, low-grade lesions smaller than 5 cm that are suprafascial can be excised with appropriate margins without adjuvant treatment. Lesions that are 5 cm or larger, are high-grade, and deep to fascia are most often treated with a combination of radiation and surgery. In the event a sarcoma is removed with inadequate margins (a scenario that is usually preceded by insufficient imaging before surgery), then the premium is on secondarily obtaining appropriate margins, most commonly with re-resection. However, in the case of a lesion in the hand or foot, multiple compartment contamination may require amputation to achieve adequate local control.

 

PREFERRED RES10-..: 4- External beam radiation and surgical resection PREFERRED RES 11-..: 1- Wide resection alone

PREFERRED RES 12…: 2- Amputation

 

CLINICAL SITUATION FOR QUESTIONS 13 THROUGH 14

Figures 13a and 13b are the MRI scans and biopsy specimen of a 64-year-old man who has coccygeal pain

 

 

 

 

 

Question 13 ..What is the most likely diagnosis?

1. Metastatic carcinoma

2. Giant-cell tumor

3. Chordoma

4. Chondrosarcoma

 

Question 14 …Based on the images and histopathology, how is this patient best treated?

1. Chemotherapy and external beam radiotherapy

2. Resection

3. Resection and chemotherapy

4. External beam radiation alone

 

DISCUSSION…The imaging demonstrates a lobular T2 hyperintense sacral lesion, which on biopsy shows physaliferous cells diagnostic of a sacrococcygeal chordoma. The histology differentiates this from metastatic carcinoma, giant-cell tumor, or chondrosarcoma. Preferred treatment is en bloc surgical resection. Although some centers employ adjuvant radiotherapy, this is of unproven benefit at this time. Evolving data suggest benefits of particle beam therapy (proton or carbon ion) from phase II studies, but this has not yet proven superior to en bloc surgery. The lesion shown is surgically accessible.

PREFERRED RESPONSE13…: 3- Chordoma PREFERRED RESPONSE14…: 2- Resection

 

Question 15 …A 56-year-old podiatrist with a negative past medical history had anterior knee pain after an injury. His radiographs, CT scan, and T1-weighted sagittal and fat-saturated axial MR images are shown in Figures 15a through 15e, respectively. After arthroscopic partial medial menisectomy, the patient was turned to the prone position and an open posterior arthrotomy and excision was performed. Low-power and high-power hematoxylin and eosin stained histologic specimens are shown in Figures 15f and 15g, respectively. Based on the history, radiographs, CT scan, MRI scans, and histologic findings, what is the most likely diagnosis?

 

1. Localized pigmented villonodular synovitis (PVNS)

2. Biphasic synovial sarcoma

3. Nodular fasciitis

4. Synovial hemangioma

 

 

 

 

 

 

 

 

 

DISCUSSION..The incidental finding in the posterior intercondylar notch of the knee in this patient represents a benign synovial hemangioma. No intralesional calcifications are shown either on the plain radiographs or CT scan. The MRI scans reveal a hypervascular lesion with

multiple filling defects, with hyperintensity on T2-weighted images and low to intermediate signal intensity on T1-weighted images. Histologically, vascular lakes within fine capillaries with a synovium on the surface of the lesion are characteristic of this condition. Many patients with synovial hemangioma present with pain, swelling, stiffness, or mechanical symptoms. As with PVNS, the disease can be localized or diffuse in nature. Surgical excision, either open or arthroscopic, is the recommended treatment. PVNS is the most common intra-articular tumor, but hypointensity in either the diffuse or localized type is characteristic on MRI scan in both T1- and T2-weighted images. Synovial sarcoma, although often found close to a joint, is not characteristically found within a joint. Nodular fasciitis is not found in intra-articular locations.

PREFERRED RESPONSE: 4- Synovial hemangioma

 

CLINICAL SITUATION FOR QUESTIONS 16 THROUGH 19

Figures 16a and 16b are the right femur radiographs of a 59-year-old man who has severe pain in his right distal thigh and knee with no significant trauma and an inability to bear weight. Blood tests demonstrate anemia, serum protein electrophoresis/urine protein electrophoresis findings are negative, and electrolyte levels are within defined limits.

 

 

 

 

 

Question 16 ..Based on this patient’s history and imaging, the best next treatment step should include

1. immediate internal fixation of the fracture.

2. a skeletal survey.

3. a dual-energy radiograph absorptiometry (DEXA) scan.

4. a CT scan of the chest, abdomen, and pelvis with a whole-body bone scan.

 

Qu 17 ..No additional bony lesions were noted. What is the most appropriate next step?

1. Bone marrow biopsy

2. Immediate internal fixation of the fracture

3. Biopsy of the fracture site

4. Chemotherapy initiation

 

Question 18 ...The final results of the patient’s presurgical studies reveal a large solid mass in the right kidney. He was brought to the operating room and a frozen section of his femur revealed the findings seen in Figure 16c. What is the best treatment option in this setting?

1. External fixation

2. Retrograde intramedullary rod

3. Distal femoral resection with megaprosthesis

4. Locking plate fixation with allograft of the defect

 

Question 19 ..Approximately what percentage of the time does an unknown primary cancer get identified as part of a full metastatic work-up that includes radiographs; blood tests; a CT scan of the chest, abdomen and pelvis; whole-body bone scan; and biopsy of the metastatic focus?

1- 45%

2- 65%

3- 85%

4- 100%

 

DISCUSSION…Metastatic bone cancer is common, affecting nearly 5.3% of the nearly 5 million people with cancer in the United States each year. This is a typical presentation of a patient with a newly diagnosed pathologic femur fracture. Without a known history of cancer, this presentation should initiate a complete metastatic work-up including a radiograph of the pathologic site; blood tests; whole-body bone scan; and a CT scan of the chest, abdomen, and pelvis. Additional imaging at the site of concern such as an MRI scan or CT scan may be helpful in certain cases. The next step is to obtain a biopsy of lesional tissue before proceeding to immediate fixation. However, it is important to note that this lesion may be a primary cancer for which case resection or amputation is necessary. A skeletal survey would be helpful in the setting of multiple myeloma. A DEXA scan has no value in this clinical setting. A bone marrow biopsy should be considered in the case of myeloma, but not metastatic carcinoma. Chemotherapy cannot be initiated in any case without a tissue diagnosis. The knowledge that the patient was found to have a large solid renal mass is highly suspicious for renal cell carcinoma, which is among the 5 most common primary carcinomas to metastasize to the bone (breast, lung, thyroid, kidney, and prostate).

Treatment of the femur should focus on a robust repair (whether biologic or not) to outlive the patient. A distal femoral resection with megaprosthesis is the most durable option for periarticular renal cell carcinoma metastasis, which is known to respond poorly to radiotherapy. The pathology shown is classic for a clear cell carcinoma of the kidney. In current practice, most primary cancers are identified as the result of a metastatic work-up. Approximately 85% to 90% of primaries are determined from the history, physical, blood tests, imaging, and biopsy results.

PREFE RES16..: 4- a CT scan of the chest, abdomen, and pelvis with a whole-body bone scan. PREFERRED RESPONSE 17..: 3- Biopsy of the fracture site

PREFERRED RESPONSE 18..: 3- Distal femoral resection with megaprosthesis PREFERRED RESPONSE 19..: 3- 85%...

 

CLINICAL SITUATION FOR QUESTIONS 20 THROUGH 23

Figures 20a and 20b are the radiographs of an 83-year-old active, independent, and healthy woman who has experienced 2 months of right lower thigh and knee pain. Her pain increased progressively over the course of several weeks. While exiting a car she “bumped” her knee against the door, felt a “crack,” and developed excruciating pain. She could no longer ambulate and was brought to the hospital.

 

Question 20..Based on imaging alone, what does this bone lesion most closely resemble?

1. Multiple myeloma

2. Nonossifying fibroma

3. Metastatic renal cell carcinoma

4. Enchondroma

 

Question 21..Figures 20c through 20e show the biopsy performed of the above-noted lesion. Based on the clinical history, radiograph, and biopsy, what diagnosis is most likely?

1. Enchondroma

2. High-grade osteosarcoma

3. Metastatic renal cell carcinoma

4. Dedifferentiated chondrosarcoma

 

Question 22 …What treatment option carries the lowest risk for local recurrence?

1. Excision of tumor followed by open reduction with internal fixation

2. Megaprosthetic reconstruction of the femur and knee after tumor resection

3. Above-the-knee amputation with wide surgical margin

4. Revision total knee arthroplasty with long-cemented stem after tumor resection

 

Question 23..What is the most likely site of metastatic disease in patients with this diagnosis?

1. Liver

2. Lungs

3. Brain

4. Kidneys

 

 

 

DISCUSSION…This patient has a pathologic femur fracture. Her history suggests that her pain was emanating from an impending fracture. The initial radiograph reveals a well-mineralized lesion within the intramedullary canal with punctate calcifications. This by itself suggests an enchondroma or low-grade chondroid lesion. It is important to note that enchondromas in the long bones rarely cause pathologic fracture. That is not the case when they are present in the hands and feet, where biologically they act more aggressively. Typically, a more aggressive appearance such as cortical thinning or breach, soft-tissue mass, or periosteal elevation suggests a chondrosarcoma.

Unfortunately, a pathologic fracture makes the images somewhat more difficult to interpret, which was the case with her MRI and CT scans. There is no evidence from her radiographs that this is anything but a chondroid tumor. Multiple myeloma often involves a radiolucent “punched out” lesion. Nonossifying fibromas are seen in children and are well circumscribed, eccentric radiolucent lesions. Metastatic renal cell carcinoma rarely demonstrates matrix on a radiograph. The histopathology clearly shows a cartilage-based tumor. The chondroid tissue appears low grade. However, in an adjacent region there is a high-grade component seen both on the low power view and the second higher-power sample that does not resemble cartilage. This is highly suggestive of a dedifferentiated chondrosarcoma. This signifies that a portion of the original tumor (low-grade chondrosarcoma), which resembled the tissue of origin, converted into a different cell lineage with more aggressive properties (nearly any type of high-grade sarcoma). These dangerous tumors are highly malignant, with average 5-year survivals of about 50%. Local recurrence in the setting of a pathologic fracture will be high secondary to spillage of tumor into the fracture hematoma and disturbed compartments. In this case, an above-the-knee amputation with a wide surgical margin would offer the lowest risk for local recurrence, but at the expense of the most functional loss, especially in this age group. The most likely site of metastatic disease from nearly any sarcoma is the lungs. Therefore, patients have their lungs surveyed with at least a chest radiograph or, in most cases, a CT scan.

PREFERRED RESPONSE20-: 4- Enchondroma

PREFERRED RESPONSE21-..: 4- Dedifferentiated chondrosarcomas

PREFERRED RESPONSE22-..: 3- Above-the-knee amputation with wide surgical margin PREFERRED RESPONSE23-..: 2- Lungs

 

Question 24 ..A 14-year-old boy has had wrist pain for 3 weeks. Radiographs are shown in Figures 24a and 24b. His MRI scans are shown in Figures 24c through 24f. Representative histology is shown in Figures 24g through 24i. The most likely diagnosis is

1. aneurysmal bone cyst.

2. fibrous dysplasia.

3. giant-cell tumor.

4. osteoblastoma.

 

 

 

 

 

 

DISCUSSION…The combination of immature woven bone with osteoblastic rimming surrounded by a vascular fibrous bland stroma seen in Figure 24i and scattered giant cells within the lesion seen in Figure 24h should arouse the suspicion of osteoblastoma.

Osteoblastoma most often is diagnosed in adolescents and young adults, with 75% of patients younger than 25 years of age at diagnosis. Within tubular bones, osteoblastoma most often arises in the metadiaphyseal region, but it is more commonly seen in the spine within the posterior elements. The lesion is well-defined on radiographs, with lucent to mixed lucent and blastic areas. The MRI scan findings reveal low to intermediate signal intensity on T1- and intermediate to high signal intensity on T2-weighted images. Neoplastic woven bone can be seen in Figure 24g, and osteoclasts are shown in Figures 24h and 24i. Although the bone is expansile in appearance on radiologic studies, there are no large vascular lakes on histology to support the diagnosis of aneurysmal bone cyst. Although there are areas of woven bone as in fibrous dysplasia, the appearance of osteoblastic rimming rules against this diagnosis. The location and histology of the tumor in this case are inconsistent with giant-cell tumor of bone, the latter being a metaepiphyseal tumor histologically comprising giant cells within a background of stromal cells having nuclei identical to those of the giant cells. PREFERRED RESPONSE: 4- osteoblastoma.

 

RESPONSES FOR QUESTIONS 25 THROUGH 29

 

1. Osteosarcoma 2- Ewing sarcoma

   3- Aneurysmal bone cyst 4- Giant-cell tumor

   5- Dedifferentiated chondrosarcomas 6- Metastatic disease of bone 7- Multiple myeloma 8- Chordoma

   9- Rhabdomyosarcoma 10- Desmoid

   11- Parosteal osteosarcoma

    

   Match the condition above with the clinical scenario below.

    

   Question 25 ..A 17-year-old girl has knee pain. The imaging shows a distal femur lesion with an adjacent soft-tissue mass. The cortex is expanded and there is periosteal reaction. There appears to be a cloud-like density within the lesion.

    

   Question 26 …A 44-year-old man has a sacral mass. There is a soft-tissue extension of the mass with bone involvement centrally within the sacrum. The patient is told that the lesion is radiosensitive.

    

   Question 27 of 143

   A 13-year-old boy with thigh pain has an enlarging soft-tissue mass. Radiographs show a mid-diaphyseal lesion with a sunburst pattern of periosteal reaction. A needle biopsy shows small round blue cells.

    

   Question 28 of 143

   An 8-year-old girl has an enlarging mass in her right shoulder. It involves the deltoid and has a heterogenous pattern on MRI scan. The mass is painless and was noticed when she was getting bathed 3 months ago. A needle biopsy shows a small round blue-cell tumor.

    

   Question 29 of 143

   A 71-year-old man has a history of left hip pain radiating to his knee. The radiographs are interpreted as osteoarthritis of the hip. He receives a hip injection, but does not experience relief. A CT scan shows a periacetabular osteolytic lesion with punctuate areas of calcification and a large soft-tissue mass.

    

   DISCUSSION…Osteosarcoma is the most common malignant bone tumor and usually involves the metaphysis of long bones in skeletally immature patients. It is a bone-forming tumor that often has a cloud-like matrix, which indicates new bone formation. Ewing sarcoma is more common in the diaphysis. Bone involvement is often accompanied by a soft-tissue mass. It occurs in a similar age group as osteosarcoma. Ewing sarcoma is radiosensitive; however, radiation is reserved primarily for nonsurgical anatomic locations. Histologically, it is in the family of small round blue-cell tumors. Rhabdomyosarcoma is a high-grade soft-tissue sarcoma most commonly seen in children. Like most soft-tissue sarcomas, it often presents as an enlarging soft-tissue mass. It is treated with chemotherapy and surgical resection. Radiation may also be used to reduce risk for local recurrence. Rhabdomyosarcoma is in the family of small round blue-cell tumors. Chordoma occurs in 2 locations; the central portion of the lower spine, usually the sacrum, and the base of the skull (the clivus). It is a radiosensitive tumor; however, resection with a negative margin is the recommended treatment. Dedifferentiated chondrosarcoma is a high-grade malignant tumor.

   Histologically, areas consistent with both chondrosarcoma and osteosarcoma are often found. Other high-grade tumors have also been described in combination with chondrosarcoma, such as malignant fibrous histiocytoma of bone. In the pelvis, it can be difficult to see on radiographs, and the symptoms can be confused with more common entities such as osteoarthritis or Paget disease. The prognosis for these patients is poor, and chemotherapy use is controversial.

    

   PREFERRED RESPONSE 25-….: 1- Osteosarcoma PREFERRED RESPONSE 26 -….: 8- Chordoma

   PREFERRED RESPONSE27 -….: 2- Ewing sarcoma PREFERRED RESPONSE 28-…: 9- Rhabdomyosarcoma

   PREFERRED RESPONSE 29-… : 5- Dedifferentiated chondrosarcoma

    

   Question 30 ..Figure 30a is the radiograph taken in the emergency department of a 20-year-old man with pain and swelling in his right-dominant arm. His MRI scan is seen in Figure 30b, and his histopathology is shown in Figure 30c. What is the most likely diagnosis?

    

    

   1. Ewing sarcoma

   2. Langerhans cell histiocytosis

   3. Osteosarcoma

   4. Osteomyelitis

    

   DISCUSSION…The imaging shows a permeative lytic diaphyseal lesion with malignant periosteal reaction and a large soft-tissue mass. The histology shows a small round blue-cell tumor consistent with Ewing sarcoma or lymphoma; genetic or immunohistochemical studies can be used for the final differentiation. Langerhans cell histiocytosis or osteomyelitis would not present this histology. Osteosarcoma would more likely be metaphyseal and would show osteoid production on radiographs and histology. PREFERRED RESPONSE: 1- Ewing sarcoma

    

   Question 31 ..An 18-year-old woman has had a right thigh mass for “a long time.” She has found it increasingly difficult to ambulate. Her medical history is unremarkable, with the exception of hypertension. On clinical examination, a fullness is appreciated in the popliteal fossa. The neurovascular status of the distal extremity is intact. Anteroposterior and lateral radiographs are shown in Figures 31a and 31b. A lateral T2-weighted MRI scan is shown in Figure 31c. The histology is seen in Figure 31d. What is the most likely diagnosis?

    

    

    

   1. Aneurysmal bone cyst

   2. Osteosarcoma

   3. Periosteal lipoma

   4. Parosteal osteosarcoma

    

   DISCUSSION…The radiographs indicate a bone-forming tumor that has intramedullary and extramedullary components. The MRI scan confirms the extent of the tumor. Parosteal osteosarcomas are generally surface tumors sparing the medullary canal, although extension into the canal can occur. However, the histology is low-grade with a well-differentiated fibrous stroma, unlike this case. The histology here shows pleomorphic cells, with the haphazard tumor bone deposition consistent with a high-grade conventional osteosarcoma. Telangiectatic osteosarcoma is associated with vast lakes of blood, which are usually seen on MRI scan as fluid-fluid levels. In this patient, there was a single fluid-fluid level on MRI scan, but the histology provided did not show lakes of blood. Aneurysmal bone cyst and periosteal lipoma are both benign lesions and not consistent with the histology shown. PREFERRED RESPONSE: 2- Osteosarcoma

    

   CLINICAL SITUATION FOR QUESTIONS 32 THROUGH 36

    

    

   A 68-year-old woman is referred for left thigh pain. Her medical history includes Hypertension, diabetes, and adenocarcinoma of the breast treated with surgery, chemotherapy, and radiation 3 years ago. She currently is on aromatase therapy. She is unable to ambulate secondary to pain, is limited to a walker, and requires narcotic medications. She has no other pain but agrees to your recommendation that she urgently be sent to the hospital.

    

   Question 32..After viewing the radiographs in Figures 32a and 32b, what is the most appropriate next step?

   1. Surgical stabilization

   2. Biopsy of the lesion

   3. Further imaging

   4. Immediate administration of bisphosphonates

    

   Question 33 …The patient is scheduled for surgery to stabilize the bone. According to the Mirels Scoring System, what is most likely related to risk for pathologic fracture?

    

   1. Pathology of the original tumor

   2. Gender

   3. Location of the lesion

   4. Age of the patient

    

   Question 34 …The surgeon decides to obtain a biopsy before stabilization; new lesions are unrelated to previous malignancies in what percentage of cases?

   1- 5%

2. 15%

3. 25%

4. 35%

 

Question 35 …Chance for fracture healing often is a factor in surgical decision making for reconstruction of pathologic lesions. Among the diagnoses listed below, which grouping represents fracture healing likelihood from least likely to most likely?

1. Breast carcinoma, lung carcinoma, multiple myeloma,

2. Multiple myeloma, breast carcinoma, lung carcinoma

3. Lung carcinoma, multiple myeloma, breast carcinoma

4. Lung carcinoma, breast carcinoma, multiple myeloma

 

Question 36 ..Which intervention should be added to this patient’s care to best prevent future skeletally related events (SRE)?

1. Inferior vena cava (IVC) filter placement

2. Bisphosphonates

3. External beam radiation

4. Tc-99 whole-body bone scan at regular intervals

 

DISCUSSION…A new lesion in a patient with known carcinoma but without bone disease needs to be evaluated before stabilization. As shown by Clayer and associates, as many as 15% of new bone lesions with a history of known carcinoma will be from a different primary and should be worked up before surgery. Evaluation with appropriate imaging will allow for identification of other lesions that may be easier to biopsy or require fixation. Mirels classified the chance that a metastatic lesion in the extremities will go on to pathologic fracture based on 4 factors: size, site, type of bone reaction, and pain level. Prophylactic fixation is recommended for scores of 8 or 9 and above, with a 15% to 30% chance of fracture, respectively. The pathologic diagnosis is not involved with the chance for fracture based on the Mirels classification.

Pathologic diagnoses, however, are associated with healing likelihood of lesions and the time at which replacement should be considered over reduction and internal fixation. While not technically metastatic disease, the systemic nature of multiple myeloma functions like a widespread disease. Lung carcinoma has a very low healing likelihood, followed by breast cancer, renal cancer, and myeloma, and should be factored when choosing methods of surgical stabilization as shown by Gainor and associates.

Finally, because these patients are at significant risk for more lesions and skeletal-related events, appropriate systemic treatment with bisphosphonates has been shown to help with hypercalcemia and reduce SREs. IVC filter placement has been advocated to reduce risk for fatal pulmonary embolism in patients with lower-extremity metastatic disease undergoing operative intervention.

Radiation is indicated for local control, and monitoring with bone scans will help identify impending lesions sooner than relying on pain symptoms alone.

 

PREFERRED RESPONSE32…: 3- Further imaging PREFERRED RESPONSE 33-..: 3- Location of the lesion PREFERRED RESPONSE 34-…: 2- 15%

PREFERRED RESPONSE 35…..:4- Lung carcinoma, breast carcinoma, multiple myeloma PREFERRED RESPONSE 36-…: 2- Bisphosphonates

 

Question 37..Figures 37a and 37b are the lateral and anteroposterior (AP) radiographs of a 60-year-old man with a remote history of renal cell cancer. A needle biopsy of the lesion is shown in Figure 37c. The bone destruction that occurs in this process is a result of

 

 

 

1. tumor cells.

2. cytokines secreted by the tumor.

3. host bone osteoblasts.

4. osteoprotegerin.

.

DISCUSSION…The lateral and AP radiographs of the elbow reveal a lucent lesion consistent with metastatic disease, and, specifically, metastatic renal cancer. The histology is consistent with clear cell carcinoma. Tumor cells do not destroy host bone. Rather, cytokines from the tumor stimulate osteoclasts or osteoblasts to destroy or generate new bone, respectively. Osteoblasts secrete receptor activator of nuclear factor kappa beta ligand (RANKL), and osteoclasts have receptors for RANKL. This causes an increase in osteoclast precursors, resulting in increased bone destruction. Osteoprotegerin is a decoy receptor that binds to RANKL and inhibits an increase in osteoclasts.

PREFERRED RESPONSE: 2- cytokines secreted by the tumor

 

Question 38 ..Figures 38a and 38b are the histopathology of an otherwise healthy 31-year-old man who had a growing mass excised from his forearm with local anesthetic and no preoperative imaging. The mass was documented to be subfascial and larger than 5 cm.

What is the best local treatment option?

 

 

1. Observation

2. Radiation only

3. Chemotherapy only

4. Re-excision and radiation

 

DISCUSSION…The misdiagnosis of a soft-tissue mass is fairly common. However, in this case the first indication that the presumed diagnosis is incorrect is supported by significant growth over a short time period. Generally, lipomas and many other benign soft-tissue masses grow slowly over years rather than weeks or months. On MRI scan, a lipoma would classically demonstrate homogenous high-signal intensity on a T1 sequence and fairly low-signal intensity on a T2 sequence. No imaging was done before surgery, but a high-grade sarcoma generally shows a heterogenous signal on T1 and T2 sequences that is distinctly different than the pattern of a lipoma. The histopathology is consistent with a high-grade sarcoma A spindle-cell tumor with hypercellularity, anaplasia, and pleomorphism. Mitotic figures are also noted, suggesting rapid turnover and growth. This is a high-grade sarcoma that is treated with wide surgical excision and observation is not recommended. External beam radiation is often used as an adjuvant either before or after surgery to help decrease the local recurrence rate. Radiation alone would not be sufficient treatment. The use of chemotherapy is controversial. In the setting of a “whoops” or unintended resection of a high-grade soft-tissue sarcoma, re-excision of the tumor bed with radiation is generally indicated. The radiation is used to eliminate microscopic contamination.

However, there is some evidence to support surgery alone for superficial (subcutaneous) sarcomas. PREFERRED RESPONSE: 4- Re-excision and radiation

 

Question 39 …Figure 39a is the anteroposterior radiograph of a 51-year-old man who has had a painless soft-tissue mass on his left wrist for 2 months. MR sequences are shown in Figures 39b through 39d. A biopsy was performed and shown in a low-power hematoxylin and eosin photomicrograph in Figure 39e. The most appropriate treatment for this lesion is

1. a diet that reduces uric acid production.

2. wide local resection followed by radiotherapy.

3. marginal excision.

4. observation until the mineralization matures, and then excision and radiotherapy to prevent recurrence.

 

 

 

DISCUSSION…The tumor seen here is a giant-cell tumor of the tendon sheath. A solid lesion larger than 1.5 cm in the wrist warrants biopsy to exclude malignancy. Synovial sarcoma should be considered in mineralized periarticular masses; histology does not support this diagnosis. The 3 most common benign tumors of the wrist are ganglion cysts, giant-cell tumors of tendon sheath, and hemangiomas. Radiographs are nonspecific but may reveal extrinsic erosions of bone by giant-cell tumor of tendon sheath. MR findings of prominent low-signal intensity (seen with T2-weighting) and “blooming” artifact from the hemosiderin (seen with gradient-echo sequences) are nearly pathognomonic of this diagnosis as seen here. Pathology shows hemosiderin-laden macrophages and giant cells as seen in the histology. Uric acid reduction would be indicated for gout and wide local excision for a soft-tissue sarcoma. Observation awaiting mature mineralization would apply to heterotopic ossification. PREFERRED RESPONSE: 3- marginal excision.

 

CLINICAL SITUATION FOR QUESTIONS 40 THROUGH 43

Figures 40a through 40c are the radiograph, bone scan, and histology of a 68-year-old man who has had 3 months of pain in his left thigh with weight bearing. He has no history of cancer and no illnesses.

 

 

Question 40 …The lesion seen in Figures 40a and 40b may best be described as

1. malignant.

2. benign latent.

3. benign aggressive.

4. inflammatory.

 

Ques 41..The origin of the lesion seen in Figures 40a and 40b may best be determined with

1. CT scan of the chest, abdomen and pelvis.

2. CT scan of the lesion.

3. MRI scan.

4. I-131 scan.

 

Question 42 ..The best next diagnostic step after imaging and staging is

1. prophylactic nail with reamings sent for permanent pathology.

2. biopsy.

3. C-reactive protein.

4. MRI scan.

 

Question 43 ..The orthopaedic surgeon obtains tissue with the histology shown in Figure 40c. Treatment should consist of

1. surgical stabilization.

2. surgical stabilization and radiation.

3. excision and endoprosthesis.

4. radiation.

 

DISCUSSION….The history and images show a lytic, malignant solitary bone lesion with a pathologic fracture in an adult patient. In a patient older than age 50 with a lytic bone lesion, metastatic disease is the most likely diagnosis. Prostate, thyroid, breast, lung, and kidney are the most common cancer sources for a primary lesion. The most likely test that will identify the primary malignancy is a CT scan of the chest, abdomen, and pelvis. Because no previous cancer history exists, a biopsy of the bone lesion is necessary to make a diagnosis and to rule out a primary bone sarcoma, for which the treatment would vastly differ. In a patient with no cancer history, the biopsy is obtained to exclude a primary bone malignancy before surgical intervention. The histology in this case shows nests of cohesive cells mimicking glandular structures consistent with a carcinoma, so surgical stabilization may be undertaken. Cementation and curettage alone will not address the mechanical instability, excision and endoprosthesis would entail a larger surgery than is needed, and radiation alone will not address the mechanical instability. In the setting of placing an intramedullary nail, the bone will require radiation to eliminate residual disease within the femur.

PREFERRED RESPONSE 40- …..: 1- malignant.

PREFERRED RESPONSE 41..,,,,,,,: 1- CT scan of the chest, abdomen and pelvis. PREFERRED RESPONSE 42………: 2- biopsy.

PREFERRED RESPONSE 43……….: 2- surgical stabilization and radiation.

 

 

 

Question 44 Figures 44a and 44b are the anteroposterior hand and humerus radiographs of a 5-year-old girl who has painful masses in her hand. Her parents noted concern about her left wrist and upper arm, which have been sites of occasional pain. Examination reveals obvious deformity of the left upper arm with shortening, mild bowing, and nonmobile masses within each finger. No evidence of lesions is seen on her skin or in the soft tissues. What is the approximate lifetime incidence of malignant degeneration from this condition?

 

1- 1% to 5%

2- 10% to 25%

3- 50% to 70%

4- 80% to 100%

 

DISCUSSION…This is a good example of a patient with Ollier disease, or multiple enchondromatosis. The lack of skin or soft-tissue findings suggests there are no signs of angiomas/hemangiomas that are required to make the diagnosis of Maffucci syndrome. Ollier disease is associated with malignant degeneration of benign cartilaginous tumors into chondrosarcomas with variable reported rates. The reported incidence ranges from 10% to 25%. It is suggested that patients with Maffucci syndrome have cancer rates approaching 100%; however, in many of these cases the malignancy is not from sarcomatous transformation of an enchondroma, but rather other primary sources such as the gastrointestinal tract. PR:2-10% to25%

 

CLINICAL SITUATION FOR QUESTIONS 45 AND 46

Figures 45a through 45c show the sagittal proton density, T2-weighted, and axial gradient echo MRI scans of a 34-year-old active woman with knee pain and swelling. Radiographs show only an effusion.

 

 

 

Question 45 ..The most likely diagnosis is

1. synovial sarcoma

2. synovial chondromatosis.

3. pigmented villonodular synovitis (PVNS).

4. posttraumatic hemarthrosis.

 

Question 46 ..First-line treatment recommendations include

1. synovectomy.

2. arthrocentesis, compressive wrap, and rest.

3. en bloc resection.

4. intra-articular radioactive nucleotide injection.

 

DISCUSSION…The MRI scans reveal classic findings of PVNS with low signal on proton density and T2 sequences and evidence of “blooming” on gradient echo sequences. A discrete mass suggestive of a sarcoma (which would typically appear dark on T1 and bright on T2, but heterogenous and enhancing) is not seen, and synovial sarcomas rarely arise in an intra-articular location. Cartilaginous nodules of synovial chondromatosis are not seen, and the abnormal synovial process indicates that this is more than just a posttraumatic hemarthrosis. Treatment is synovectomy; radiotherapy is reserved for select recurrent cases. Arthrocentesis would be used for a simple hemarthrosis, and resection used for a sarcoma.

 

PREFERRED RESPONSE: 3- pigmented villonodular synovitis (PVNS). PREFERRED RESPONSE: 1- synovectomy.

 

RESPONSES FOR QUESTIONS 47 THROUGH 52

1. Ultrasound

2. MRI scan of the thigh

3. Chest CT scan and whole-body bone scan

4. Positron emission tomography (PET) scan

5. Presurgical radiation therapy

6. Marginal resection

7. Radical resection and postsurgical radiation

8. Transverse incision centered over the mass

9. Incision centered over the mass in line with long axis of limb

10. Sentinel node biopsy

11. Core needle biopsy

For each soft-tissue mass clinical scenario or question below, match the most appropriate next evaluation or treatment step listed above.

 

Question 47 .A 34-year-old man with a large and rapidly enlarging deep mass in his thigh.

 

Question 48 ..A 56-year-old woman with a heterogenous retroperitoneal soft-tissue mass larger than 5 cm (as imaged on MRI scan) that first was noticed after a slip and fall. Staging study findings are negative.

 

Question 49 ..A 65-year-old man with an American Joint Committee on Cancer (AJCC) III anterior thigh sarcoma is considering treatment options. What treatment regimen is associated with a higher rate of wound healing complications after surgery?

 

Question 50 ..A 44-year-old woman elects surgical treatment of an intramuscular lipoma. What is the preferred surgical treatment?

 

Question 51..A 29-year-old man with a large and enlarging upper arm deep mass has an inconclusive needle biopsy.

 

Question 52 ..A 60-year-old woman with a clear cell sarcoma of the foot has no evidence of disease elsewhere after standard staging of a soft-tissue sarcoma. What additional evaluation is recommended?

 

DISCUSSION..In patients with rapidly enlarging painless masses, particularly those that are either large or deep, the diagnosis of a soft-tissue sarcoma should be entertained. Characteristics that are concerning are masses larger than 5 cm in largest dimension that are subfascial and heterogenous on MRI scan. MRI scan is the preferred imaging

modality for evaluation of soft-tissue sarcomas because it can delineate location of the lesion, involvement of neurovascular structures, intra-articular involvement, and underlying signal alteration in the osseous structures. Most patients relate the onset of their symptoms to a traumatic event, and the interpretation of the MRI scan can include a hematoma. Ultrasound is more commonly used to confirm the clinical impression of a cyst and to distinguish cystic from solid masses.

A core needle biopsy can easily be performed in an outpatient setting or with image guidance to aid in the diagnosis. Core needle biopsies preserve the architectural relationship of cells, which is important in the diagnosis of mesenchymal lesions. A fine-needle aspiration allows cytologic but not histologic analysis, and generally is not favored for the diagnosis of a sarcoma. If an open biopsy is performed, the incision must be oriented in line with the long axis of the extremity to minimize contamination of surrounding structures. Meticulous hemostasis and closure of the tumor

 

pseudocapsule must be achieved to minimize local tissue contamination. An open biopsy is commonly used if an initial needle biopsy is nondiagnostic. Transverse biopsy incisions should not be used.

Presurgical radiation for sarcomas is advantageous to decrease the field of radiation and overall radiation dose, but a significant postsurgical wound-healing complication rate (up to 35%) is associated with presurgical radiation therapy.

Staging of sarcomas is important to predict prognosis. Not all sarcomas are reliably positive on a PET scan, so the preferred staging studies are CT scan of the chest and whole-body bone scan. Hematogenous spread of sarcomas is the most common route of metastatic disease, which speaks to the value of chest CT scans. Clear cell sarcomas (in addition to synovial sarcoma, angiosarcoma, epitheliod sarcoma, and rhabdomyosarcoma) have a propensity for lymphatic nodal metastatic disease, so sentinel node biopsy is considered in assessing these tumors. Recent evidence supports efficacy of sentinel node biopsy for clear cell sarcomas in particular.

 

PREFERRED RESPONSE..47…: 2- MRI scan of the thigh PREFERRED RESPONSE 48…: 11- Core needle biopsy PREFERRED RESPONSE49……: 5- Presurgical radiation therapy PREFERRED RESPONSE 50…...: 6- Marginal resection

PREFERRED RESPONSE51….: 9- Incision centered over the mass in line with long axis of limb PREFERRED RESPONSE52…..: 10- Sentinel node biopsy

 

 

 

Question 53…Figure 53 is the emergency department radiograph of a 7-year-old boy who has pain and is unwilling to use his right arm after a fall on the playground. What is the most appropriate initial treatment?

 

1. Nonsurgical treatment of the fracture

2. Aspiration and injection with methylprednisolone

3. Curettage and augmentation with bone cement and internal fixation

4. Further imaging and biopsy

 

DISCUSSION…When a unicameral cyst is present in the setting of a pathological fracture, it is best to allow the fracture to heal before administering interventions for the cyst. In some cases, waiting may obviate the need for a procedure to manage the cyst. When indicated, the initial procedure of choice is aspiration and injection of the cyst. Although many variations of the procedure exist, current evidence continues to support the role of methylprednisolone in the injection portion of the procedure. Curettage and packing may sometimes be appropriate for recalcitrant cysts, but is not indicated for this patient. These cysts are typically solitary and are not considered at risk for malignant degeneration or systemic involvement; therefore, further distant imaging and biopsy is unnecessary.

PREFERRED RESPONSE: 1- Nonsurgical treatment of the fracture

 

 

 

Question 54 ..Figure 54 is the CT scan of a 70-year-old man with progressive neck pain; there is no history of trauma, and examination is notable only for mildly decreased cervical range of motion. He is neurologically intact. He has monoclonal gammopathy of undetermined significance that has been stable for many years. Current serum protein electrophoresis is unchanged. History and examination reveal no other causes for his pain. What is the next step in clinical management?

 

1. Corpectomy and anterior fusion

2. Radiation therapy followed by multiple myeloma protocol chemotherapy

3. CT-guided biopsy

4. CT scan of the chest, abdomen, and pelvis

 

DISCUSSION…The patient has a lytic lesion of unclear etiology. Rougraff and associates demonstrated the efficacy of a protocol including history and examination, basic laboratory studies, imaging, and biopsy of the most accessible lesion in identifying the primary site of disease in patients with skeletal metastases of unknown primary. A CT scan of the chest, abdomen, and pelvis and bone scan

complete the next step of Rougraff’s protocol. Although the history suggests possible myeloma, the laboratory studies do not support transformation of monoclonal gammopathy to multiple myeloma.

For this patient, CT scan showed a primary lung cancer, and a biopsy of a

rib metastasis (much safer to biopsy than the cervical spine) confirmed metastatic adenocarcinoma.

Reflexive biopsy of a difficult and risky lesion is incorrect; staging the patient is likely to identify a safer site to access for biopsy and may identify conditions such as metastatic renal cell carcinoma that would benefit from embolization before surgery. Corpectomy and anterior fusion is incorrect because immediate surgery is not needed here (intraosseous lesion causing pain with a normal neurologic examination and mildly decreased range of motion). Radiation and chemotherapy should not be administered before a diagnosis is ascertained.

 

PREFERRED RESPONSE: 4- CT scan of the chest, abdomen, and pelvis

 

Question 55 …A 27-year-old incarcerated man was found to have a fungating mass on his anterolateral right proximal thigh. A clinical photograph is shown in Figure 55a. T1- and T2-weighted coronal MRI scans are shown in Figures 55b and 55c. The hematoxylin and eosin and CD34 stained histology are shown in Figures 55d and 55e. What is the most likely diagnosis?

 

1. Squamous cell carcinoma

2. Melanoma

3. Dermatofibrosarcoma protuberans (DFSP)

4. Desmoid tumor

 

 

 

DISCUSSION..The clinical photograph is characteristic for a large DFSP with lobules of tumor that often fungate over a long period of time. The tumor has an infiltrative growth pattern and has a high local recurrence rate if not widely resected. The tumor is characterized by the t(17;22) translocation with the gene PDGFB to the collagen 1 alpha gene. The gene fusion product is instrumental in the pathogenesis of the tumor. Histologically, the tumor is composed of uniform fibroblasts arranged in a storiform pattern. CD34, the human progenitor cell antigen, is positive.

Although squamous cell carcinoma and melanoma can often fungate, the protruding nodules of tumor clinically are not characteristic of those neoplasms. Aggressive fibromatosis is much less cellular than DFSP and has less defined margins on MRI scan.

PREFERRED RESPONSE: 3- Dermatofibrosarcoma protuberans (DFSP)

 

Question 56 ..Figures 56a and 56b are the axial short tau inversion recovery and T1 with contrast images of a 7-month-old infant who is found to have a right scapular soft-tissue mass. On examination, the mass is hard. A biopsy was performed and is shown in Figure 56c (hematoxylin and eosin, 400x). What is the optimal treatment for this patient?

 

 

1. Intralesional excision 2- Marginal excision

   3- Wide excision 4- Observation

    

   DISCUSSION…The lesion seen here is infantile fibromatosis, and advanced imaging (ultrasonography, CT scan, and MRI scan) reveals lesion extent. Involvement of adjacent structures is common, reflecting the infiltrative growth pattern often seen in these lesions. MRI scan may show characteristic features of prominent low- to intermediate-signal intensity and bands of low-signal intensity representing highly collagenized tissue. However, fibromatoses with less collagen and more cellularity may have nonspecific high-signal intensity on T2-weighted images.

   Local recurrence is frequent after surgical resection because of the aggressive lesion growth. This tumor is treated with wide excision, and chemotherapy is frequently employed as an adjunct.

   PREFERRED RESPONSE: 3- Wide excision

    

   Question 57 …Figures 57a through 57d show the radiographs and T1- and T2-weighted MRI scan sequences of the proximal femur of a 60-year-old man with progressive thigh pain. A review of radiographs taken 3 years ago reveals that the lesion is new. The biopsy specimen is shown in Figure 57e; staging studies show no other lesions, and local imaging confirms the process is confined to bone (no soft-tissue mass). The next treatment step should include

    

    

    

   1. hip disarticulation.

   2. radiotherapy.

   3. ifosfamide-based chemotherapy.

   4. wide resection and reconstruction.

    

   DISCUSSION…The radiographs and MRI scans show a cartilaginous lesion of the proximal femur with cortical thickening and cortical invasion seen on axial MRI scan. The fact that the lesion is new proves it is not an enchondroma (which would not be expected to arise de novo in an adult and would not have such significant cortical changes). Biopsy reveals an intermediate-grade chondrosarcoma with nuclear atypia in addition to permeation of trabecular bone. The treatment of choice is surgical resection and reconstruction. Hip disarticulation is not indicated because the lesion is confined to the bone without involvement of vessels or nerves. Radiotherapy would be indicated for hematopoietic or radiosensitive malignancies, but chondrosarcoma does not respond to radiation or chemotherapy. Curettage and bone cement have been advocated as treatment for low-grade chondrosarcomas. However, the clear nuclear atypia on the biopsy and the demonstration of intracortical involvement on the axial MRI scan make this a less optimal treatment choice for this patient. PREFERRED RESPONSE: 4- wide resection and reconstruction.

    

   Question 58 …The characteristic translocation and genes involved in extraskeletal myxoid chondrosarcoma is

   1- t(11;12) EWS;FLI1

2. t(12;16) TLS;CHOP.

3. t(9;22)EWS;CHN.

4. t(9;22) BCR-ABL.

.

DISCUSSION..Extraskeletal myxoid chondrosarcoma is characterized by an in-frame fusion of the genes EWS and TEC (also called CHN) involving chromosomes 9 and 22, respectively. Chronic myelogenous leukemia is also characterized by a translocation involving chromosomes 9 and 22; however, the fused genes are different. t(11;12)

EWS/FLI1 is characteristic of Ewing sarcoma/t(12;16) TLS; CHOP is characteristic of myxoid liposarcoma. PREFERRED RESPONSE: 3- t(9;22) EWS;CHN

 

Question 59 .Figures 59a and 59b are the axial T2 and T1 with contrast MRI scans of a 32-year-old woman who has a 10-year history of pain and a 1-year history of progressive swelling in her right leg. The histopathology is shown in Figure 59c. A radiograph of her leg showed no mineralizations or osseous erosions. The chromosomal abnormality that is associated with this disease is

 

 

1- t(11;22).

2- t(2;13).

3- t(X;18).

4- t(12;16).

 

DISCUSSION…The imaging shows a soft-tissue mass with histology showing a synovial sarcoma. This histology is associated with t(X;18). Ewing sarcoma is associated with t(11;22); alveolar

 

rhabdomyosarcoma t(2;13); and myxoid liposarcoma t(12;16). Although the presented monophasic histology could be consistent with other sarcomas, it does not have the characteristics of Ewing sarcoma (small round blue cells), alveolar rhabdomysarcoma (alveolar pattern), or myxoid liposarcoma (myxoid stroma and signet ring lipoblasts with a plexiform capillary network).

PREFERRED RESPONSE: 3- t(X;18).

 

CLINICAL SITUATION FOR QUESTIONS 60 THROUGH 63

A 45-year-old woman has an enlarging buttock mass. The mass is 12 cm and nonpainful. The patient first noticed it about 6 months after she had a low-impact fall. The general surgeon evaluating the patient felt this mass could be either a lipoma or a hematoma. The patient underwent a surgical procedure to remove the mass.

 

Question 60 .After evaluating the mass with a history and examination, what is the most appropriate next treatment step?

1. Observation

2. Imaging studies (MRI scan or CT scan)

3. Surgical excision

4. Open biopsy

 

Question 61 of 143..A surgical excision performed on this patient should be done with which principle in mind to minimize contamination of soft tissues?

1. Meticulous hemostasis and closure

2. Traversing multiple muscle compartments

3. Transverse incision

4. Exposing neurovascular structures

 

Question 62 ..Which description best characterizes an unplanned excision of a soft-tissue sarcoma?

1. The length of the incision is excessive.

2. The incision is oriented transversely on the extremity.

3. No imaging was obtained before surgery.

4. No radiation was given before surgery.

 

Question 63..What is the most common detrimental impact of an unplanned excision of a high-grade soft-tissue sarcoma?

1. Decreased mortality

2. Decreased recurrence

3. Increased wound complications

4. Increased functional outcome

 

DISCUSSION..This is an example of an unplanned excision. The patient has a history of trauma and a painless soft-tissue mass. The most common soft-tissue masses are benign; consequently, nononcologic surgeons may not expect a malignant sarcoma. The patient was taken to surgery with appropriate imaging and without a biopsy. If the imaging is conclusive a biopsy is not always indicated, particularly for low-grade lipomatous tumors. The surgical resection was performed through a transverse incision. It is recommended that the incision be made longitudinally in the event a wider resection is needed. The grade of the tumor is the most important aspect. Benign and low-grade tumors may be observed, whereas intermediate and high-grade tumors require a wide resection and likely perioperative radiation. The appropriate work-up for a soft-tissue mass is a careful history and examination accompanied by radiographs and cross-sectional imaging. If a biopsy is needed, it should be performed or supervised by the surgeon, who would do the final

 

resection if it proves to be a sarcoma. The most common impact of an unplanned excision is wound complications. This is because of the need for a wider surgical resection and adjuvant radiation. Mortality and recurrence have not been shown to be increased with statistical significance. Functional outcome may be compromised; however, no studies confirm that functional outcome is poorer in patients who undergo unplanned excision.

PREFERRED RESPONSE 60-,…: 2- Imaging studies (MRI scan or CT scan) PREFERRED RESPONSE 61….: 1- Meticulous hemostasis and closure PREFERRED RESPONSE 62…..: 3- No imaging was obtained before surgery. PREFERRED RESPONSE 63…..: 3- Increased wound complications

 

CLINICAL SITUATION FOR QUESTIONS 64 THROUGH 66

Figures 64a through 64c are the radiograph, MRI scan, and histology of a 53-year-old man with medial knee pain and swelling below the knee.

 

 

Question 64 ..What is the origin of the lesion seen on imaging?

1. A meniscal tear

2. A parameniscal cyst

3. Elastin deficiency

4. Translocation x;18

 

Question 65 …Arthroscopy is performed, the palpable lesion is aspirated, and no fluid is obtained. What is the best next treatment step?

1. Marginal resection of the cyst through a transverse incision

2. Marginal resection of the cyst through a longitudinal incision

3. Arthroscopic evaluation of the cyst

4. Biopsy

 

Question 66..Histology of the lesion is shown in Figure 64c. The best next treatment step is

1. radiation.

2. radiation and surgery.

3. chemotherapy.

4. observation.

 

DISCUSSION….Parameniscal cysts and soft-tissue sarcomas can easily be confused, especially when there is an intra-articular abnormality. This patient has a synovial sarcoma, which has an x;18 translocation abnormality. The lack of communication with the joint; no meniscal tear on MRI scan; a lesion that has signal characteristics that are not the same as muscle, fat, or fluid; and aspiration that yields no fluid are all characteristics of a soft-tissue sarcoma. A parameniscal cyst has a signal characteristic that is identical to the joint fluid on MRI scan and has a visible connection to the joint. When a lesion is encountered that may have malignant potential, a biopsy is imperative. Principles of an extremity biopsy—longitudinal incision, strict hemostasis, minimizing tissue plane dissection, and ensuring appropriate tissue—must be observed. Marginal resection of a soft-tissue sarcoma, especially through a transverse incision, would not be appropriate

care. A soft-tissue sarcoma is treated with radiation and surgery. Chemotherapy is controversial in this setting with no long-term benefit.

PREFERRED RESPONSE: 4- Translocation x;18 PREFERRED RESPONSE: 4- Biopsy

PREFERRED RESPONSE: 2- radiation and surgery.

 

Question 67 ..A 26-year-old woman has had a slow-growing and painful mass at the base of her ring finger for several months. Radiographs of the affected digit show no mineralization or erosions of the underlying bone. An axial T1 MRI scan is shown in Figure 67a, and a corresponding short tau inversion recovery image is shown in Figure 67b. A coronal T1 MRI scan with contrast is shown in Figure 67c. The best next treatment step is

 

 

1. referral to a sarcoma center.

2. observation.

3. excisional biopsy.

4. marginal excision.

 

DISCUSSION..The lesion seen in the images is larger than 1.5 cm and growing. Therefore, a malignant growth must be considered. Although malignant tumors of the hand are rare and clear-cell sarcoma is rarer still, the most common clinical symptom is a small

painless mass. Curative excision or amputation is the treatment of choice. Observation of a malignant lesion is not acceptable treatment, and neither an excisional biopsy nor marginal excision can achieve the wide excision necessary for this patient.

PREFERRED RESPONSE: 1- referral to a sarcoma center.

 

Question 68 ..What is the most specific immunohistochemistry staining pattern that confirms the diagnosis of desmoid tumor?

1. Membranous beta-catenin staining

2. Nuclear beta-catenin staining

3. Nuclear SMAD4 staining

4. Vimentin positivity

 

DISCUSSION…Desmoid tumors are characterized by aberrant activation of Wnt signaling resulting from mutations in the adenomatous polyposis coli and beta-catenin genes. Although a nuclear

beta-catenin staining pattern can be observed in other tumor types, it is highly specific for desmoid tumor. Vimentin positivity indicates that a lesion is a mesenchymal neoplasm, but it is not specific for desmoid tumor. PREFERRED RESPONSE: 2- Nuclear beta-catenin staining

 

Question 69 …A 30-year-old woman has progressive gait instability, back pain, and urinary retention. Figures 69a and 69b show the axial T2 and postcontrast MRI scans taken at the level of T11, and Figure 69c shows the sagittal T1-weighted image. Representative histology is shown in Figure 69d. The patient remains ambulatory, but symptoms have

progressed during the last week and she is beginning to feel weakness in her legs. Examination is notable for decreased rectal tone, lower-extremity hyperreflexia and clonus, and 4/5 motor strength throughout the lower extremities. What is the most appropriate treatment recommendation for this patient?

 

 

 

1. Margin-free en bloc spondylectomy of T11

2. Radiation therapy

3. Radiation therapy followed by anterior corpectomy and fusion

4. Transpedicular decompression and posterior stabilization followed by radiation therapy

 

DISCUSSION….This patient has symptomatic metastatic epidural spinal cord compression from synovial sarcoma with pathologic fracture and epidural extension of disease. Patchell and associates demonstrated outcomes with direct decompressive surgery followed by radiation therapy that were superior to radiation alone for patients presenting in this

manner; note that the trial excluded patients with exquisitely radiosensitive malignancies such as lymphoma and germ-cell tumors. Ibrahim and associates confirmed these results in a prospective multicenter observational study. The sagittal T1-weighted image shows other lesions at T1 and T5, confirming a metastatic process. The histology shows synovial sarcoma and excludes hematopoietic or germ-cell malignancy (very radiosensitive). Margin-free en bloc spondylectomy would be difficult to achieve considering extension of tumor into the posterior elements, degree of epidural compression, and abutment of the aorta. More important, it is difficult to justify the magnitude and risk associated with this procedure in a patient with multiple metastatic lesions.

Radiation therapy alone and radiation followed by surgery were shown in Patchell’s study to have inferior outcomes. A patient with a progressive neurologic deficit should have surgery before radiotherapy.

PREFERRED RESPONSE: 4- Transpedicular decompression and posterior stabilization followed by radiation therapy

 

Question 70 …Giant-cell tumor of bone usually involves the epiphysis of long bones. What is the next most common type of tumor involving this anatomical location?

1. Conventional chondrosarcoma

2. Aneurysmal bone cyst

3. Chondroblastoma

4. Osteoblastoma

 

DISCUSSION..Giant-cell tumor is the most common lesion involving the epiphysis, although its epicenter is usually in the metaphysis, and in the rare case of giant-cell tumor

occurring in a skeletally immature patient, giant-cell tumor is located in the metaphysis. It also can involve the flat bone of the pelvis and sacrum. Chondroblastoma exclusively occurs in the epiphysis of skeletally immature patients. It is more common than the other responses. Although conventional chondrosarcoma does not involve the epiphysis, clear-cell chondrosarcoma involves the epiphysis as well; however, it is rare and less common than chondroblastoma. Aneurysmal bone may occur in the epiphysis; however, it is often seen with other benign tumors such as chondroblastoma or giant-cell tumor. It is less common in this location than chondroblastoma.

Osteoblastoma does not classically appear at the epiphysis. It is more commonly seen in the spine or the diaphysis of long bones.

PREFERRED RESPONSE: 3- Chondroblastoma

 

CLINICAL SITUATION FOR QUESTIONS 71 THROUGH 73

Figures 71a through 71e are the radiographs, MRI scan, and CT scans of a 14-year-old-boy who has cyclical pain in his thigh. His symptoms began approximately 6 months ago. He complains of increased pain when he runs and also of pain that wakes him at night. This pain is relieved by nonsteroidal anti-inflammatory drugs (NSAIDs).

 

 

 

Question 71 ..What is the most likely diagnosis?

1. Stress fracture

2. Osteomyelitis

3. Osteoid osteoma

4. Eosinophilic granuloma

 

Question 72 ..Contemporary definitive treatment for this patient is

1. NSAIDs.

2. radiofrequency ablation.

3. intravenous antibiotics.

4. burr-down technique resection.

 

Question 73 …What is the etiology of the pain associated with this lesion?

1. Prostaglandin production

2. Gram-positive cocci

3. Osteoclast activation

4. Loss of structural integrity of the bone

 

DISCUSSION..Osteoid osteomas are most common in adolescent patients and in boys. Although these tumors can be seen in any bone, almost half are located in the femur and tibia. The significant inflammatory response to this tumor is presumed to be secondary to high levels of prostaglandin production. Characteristic pain at night is relieved by aspirin or NSAIDs. Pain can also be associated with activities and is characterized as being boring and sharp.

Radiographs often show distinctive features of thickened bone surrounding a small central core of lower density (a nidus). Thin-cut CT scan is the imaging modality of choice for visualizing the nidus, which typically lies within the cortex of the bone. An MRI scan may be misleading because of the extensive edema associated with this lesion, bringing other differential diagnoses into question. A bone scan is also associated with significant uptake but is nonspecific. Several treatment options are available, including observation and management with NSAIDs for pain

 

control, with the premise that the lesion will “burn out.” This may take several years to occur and few patients are content with this treatment regimen. Surgical resection can be accomplished with en bloc resection, but this approach is fraught with complications associated with resecting large segments of bone. A fluoroscopically assisted “burr-down” technique is effective in removing the nidus and minimizing the stress riser effect to the bone but requires an open surgery.

Radiofrequency ablation is the current first-line treatment modality for osteoid osteoma because of its high efficacy and low morbidity.

CT-guided radiofrequency ablation removal of the nidus has been successfully used with few recurrences or complications. This is a lesser procedure, compared to en bloc resection or intralesional surgery, and may be performed under general anesthesia or a regional block with sedation. The site of the tumor is identified using fine CT sections, and a radiofrequency probe is inserted into the tumor. The probe heats the tumor tissues to approximately 90°C, effectively obliterating the nidus with minimal damage to surrounding tissues. The nidus is adequately removed in 96% of patients after 1 treatment. The procedure is routinely performed on an outpatient basis by either an interventional radiologist or an orthopaedic surgeon. Most procedures take approximately 2 hours, followed by a 2-hour recovery period, after which the patient may go home with a mild pain reliever. In most cases, the patient may return to work or school in a few days with some restrictions.

PREFERRED RESPONSE: 3- Osteoid osteoma PREFERRED RESPONSE: 2- radiofrequency ablation. PREFERRED RESPONSE: 1- Prostaglandin production

 

 

 

Question 74 ...Figure 74 is the radiograph of an 11-year-old boy with pain in his left arm. Prognosis is most influenced by

 

1. stage at presentation.

2. grade at presentation.

3. response to neoadjuvant chemotherapy.

4. histologic subtype.

 

DISCUSSION…The imaging is characteristic for high-grade osteosarcoma. In patients with osteosarcoma, stage at presentation has the most prognostic impact; clinically detectable mestastases at presentation has a very poor prognosis. The other factors all influence prognosis in patients without metastatic disease. Low-grade nonmetastatic tumors have the best prognosis and are treated with surgery alone. In high-grade tumors, histologic response to neoadjuvant chemotherapy is predictive of survival. Response to chemotherapy, distal appendicular sites, and female gender were associated with improved survival in the study by Whelan and associates of 1067 patients with localized extremity osteosarcoma. Increased tumor volume after chemotherapy had an adverse effect on survival independent of histologic

response to chemotherapy. Age, high levels of alkaline phosphatase, tumor volume, 2-drug regimen, surgical margins, and histologic response to chemotherapy were important prognostic factors.

PREFERRED RESPONSE: 1- stage at presentation.

 

 

 

Question 75..Figures 75a through 75d are the radiograph, CT scan, bone scan, and biopsy of a 45-year-old man who has had a several-month history of progressive pain in his right hip and groin region. Based on these images and histology, what is the most appropriate treatment?

 

 

1. Wide resection

2. Curetting and bone grafting

3. Percutaneous cementation and radiotherapy

4. Chemotherapy and radiotherapy

 

DISCUSSION..The imaging (which includes a clear chest CT scan) demonstrates a lytic periacetabular lesion with internal matrix production and a cellular cartilage lesion on histology, diagnostic for a chondrosarcoma with negative staging. Wide excision with limb salvage is appropriate for a lesion without evidence of neurovascular encasement. Although used for select low-grade cartilage lesions in the extremity, curettage is not indicated for pelvic chondrosarcomas. Radiation and chemotherapy are not used in the treatment of conventional chondrosarcoma.

PREFERRED RESPONSE: 1- Wide resection

 

 

 

Question 76 ..Figure 76 is the radiograph of a 77-year-old patient with a history of myeloma who has had severe arm pain after opening a jar. Pain was present for 3 months prior to injury. The most biomechanically stable construct for this fracture is

 

1. intramedullary nailing (IMN).

2. IMN and cement.

3. plate.

4. plate and cement.

 

DISCUSSION…Although intramedullary nails or plates with screws, either of which may be combined with cement, may be used as internal fixation for a displaced humeral diaphyseal pathologic fracture, torsional performance is best biomechanically when the canal is filled with cement and fixed with a plate. In the largest comparative biomechanical study to date, 40 artificial humeri were divided into 5 different constructs and tested in torsion. The construct that resisted the largest load to failure was the construct at which the canal and tumor defect were filled with bone cement and the screws were inserted into dry cement. That being said, the weaknesses of the plate and cement technique include the potential for poor quality bone adjacent to and

extending away from the fracture site and difficulty in protecting the entire bone from progression of local disease. Numerous factors beyond just the biomechanics, including the patient’s disease load and comorbidities, the underlying primary disease and responsiveness to radiotherapy and other adjuvant treatments, and the location and local extent of disease, must be considered when determining the best operative technique to employ in each patient with a pathologic fracture.

PREFERRED RESPONSE: 4- plate and cement.

 

CLINICAL SITUATION FOR QUESTIONS 77 THROUGH 79

Figures 77a through 77c are the radiograph and MRI scans of a 45-year-old woman who enjoys dancing and has had left ankle pain for approximately 1 month with minimal trauma. She has slightly limited ankle dorsiflexion with a mechanical block with pain.

 

 

Question 77 of 143…What process most likely led to the pathology?

1. Synovial metaplasia

2. Posttraumatic heterotopic ossification

3. Malignant chondroid development

4. Neoplastic proliferation of a mixed epithelial and spindle-cell lesion

 

Question 78 ..An anterior approach to the ankle is chosen to resect this lesion. From medial to lateral, what are the structures just below the level of the ankle joint?

1. Extensor hallucis longus (EHL) tendon, tibialis anterior (TA) tendon, deep peroneal nerve, anterior tibial artery, extensor digitorum longus (EDL) tendon

2. TA, EHL, anterior tibial artery, deep peroneal nerve, EDL

3. TA, EHL, EDL, deep peroneal nerve, anterior tibial artery

4. TA, deep peroneal nerve, anterior tibial artery, EHL, EDL

 

Question 79 ..The patient undergoes recommended surgery and minimal joint damage is found. How should she be counseled regarding her future prognosis?

1. High risk for local recurrence, moderate risk for metastases

2. High risk for local recurrence, no risk for metastases

3. Low risk for local recurrence, moderate risk for metastases

4. Low risk for local recurrence, no risk for metastases

 

DISCUSSION…This patient has history and imaging consistent with synovial chondromatosis (synovial osteochondromatosis). This condition most often is seen in larger joints, particularly the knee, but has been well described in the ankle. The most common cause is primary synovial chondromatosis, which is a benign proliferative chondroid metaplasia of the synovium. These can exist in various states of calcification. In this patient, the radiographs and MRI scan reveal multiple well-calcified lesions in the anterior portion of the joint with an effusion.

Secondary synovial chondromatosis can occur after trauma in the joint but is most likely related to degenerative changes in the articular cartilage or meniscus/labral tissue. Heterotopic ossification is rarely intra-articular, and would more likely have only 1 mass. Neoplastic chondroid development would be a chondrosarcoma, which is exceedingly rare in an intra-articular location, and, even with calcification, would be a solitary mass. Synovial sarcoma is often seen in the foot and ankle, but is usually extra-articular nonsynovial with a mixed epithelial and spindle-cell morphology.

Treatment of synovial chondromatosis is resection of the lesions and synovectomy. Combined anterior and posterior approaches often can be used, and arthroscopy often is helpful. Without significant removal of joint structures, there should be minimal instability after surgery. A single surgery should handle the problem, but there is a small chance of local recurrence. As a benign process, synovial chondromatosis does not metastasize.

PREFERRED RESPONSE: 1- Synovial metaplasia

PREFERRED RESPONSE: 2- TA, EHL, anterior tibial artery, deep peroneal nerve, EDL PREFERRED RESPONSE: 4- Low risk for local recurrence, no risk for metastases

 

Question 80 ..Figures 80a through 80d are the radiographs and MRI scans of a 16-year-old girl who requires crutches because she is unable to bear weight on her right lower extremity. The pain has progressed over 2 months despite nonsurgical treatment.

Treatment at this point should include

 

 

 

1. continued observation.

2. aspiration and injection with methylprednisolone.

3. curettage and grafting.

4. wide margin resection.

 

DISCUSSION..This lesion represents a nonossifying fibroma (NOF). In general, NOFs are found incidentally and require no treatment other than serial follow up for a period of time to document stability. However, when they are painful, particularly with weight bearing, the likelihood of impending or evolving pathological fracture must be considered. In this patient, curettage and grafting with or without internal fixation is the surgical treatment of choice. Although aspiration and injection with methylprednisolone is appropriate for unicameral bone cysts, it has little role in the management of NOF. Wide margin resection is reserved for malignancy, which is not evident in this clinical scenario. PREFERRED RESPONSE: 3- curettage and grafting.

 

Question 81 ..A previously healthy 60-year-old woman has a T5 pathologic compression fracture secondary to metastatic renal cell carcinoma. She has myelopathy with severe pain upon sitting from a supine position. The adjacent thoracic levels are unaffected. On MRI scan, there is minimal space available for the cord because of epidural involvement. What is the optimal treatment method at this time?

1. Surgical decompression and instrumented fusion

2. Surgical decompression without fusion

3. Image-guided intensity-modulated radiation therapy

4. Chemotherapy

 

DISCUSSION..Data strongly support surgical treatment for spinal metastases when neurologic compromise and/or mechanical instability are present. In this patient, pain upon sitting from a supine position is a sign of mechanical instability. Although radiation therapy and chemotherapy are appropriate for the treatment of spinal metastases in other circumstances, the optimal treatment method in this case is to surgically decompress the affected level and restore mechanical stability by fusing the motion segment.

PREFERRED RESPONSE: 1- Surgical decompression and instrumented fusion

 

Question 82 ..Figures 82a and 82b are the MRI scans consisting of a T2 coronal sequence and axial T1 pulse sequence of a 38-year-old man who has had right thigh pain and a mass for 4 months since he pulled his hamstring. The presumed diagnosis considering his clinical history and evaluation of the MRI scan was hematoma and the mass was evacuated. The histology is shown in Figures 82c and 82d. Next treatment steps should include

 

 

 

 

1. physical therapy to accelerate healing and improve function.

2. a complete hematologic work-up to evaluate a bleeding disorder.

3. tumor bed excision and radiation to reduce local recurrence.

4. radiotherapy to complete definitive treatment of this problem.

 

 

DISCUSSION..Unplanned excisions of soft-tissue sarcomas occur with alarming frequency and result in high rates of residual disease, potentially affecting local control and local morbidity.

Patients with unplanned excisions who undergo limb-salvage procedures require more extensive surgical procedures involving free flaps and skin grafting and more adjuvant radiotherapy; amputation also may be required. Unplanned excisions of high-grade soft-tissue sarcomas result in increased rates of local recurrence but do not diminish disease-specific survival. Patients with unplanned excisions of high-grade sarcomas require adequate surgical excision and radiation.

Radiation alone or physical therapy is incomplete treatment in this setting. Soft-tissue sarcomas are often mistaken for spontaneous hematomas because of central tumor necrosis and intratumoral bleeding, but a hematologic evaluation in a patient with a soft-tissue sarcoma is not warranted.

PREFERRED RESPONSE: 3- tumor bed excision and radiation to reduce local recurrence.

 

Question 83 ….Figures 83a through 83c are the radiograph and MRI scans of a 16-year-old girl who had posterior knee pain after a dance recital 3 weeks ago; the pain resolved 1 week ago with ibuprofen use. What is the appropriate treatment for this patient?

 

 

1. Biopsy and resection of lesion

2. Observation and serial radiographs

3. Tc-99 whole-body bone scan and fine-cut CT scan

4. Evaluation by a pediatric oncologist

DISCUSSION…The images reveal a small reactive-type lesion in the posteromedial aspect of the distal femur consistent with an avulsive cortical irregularity. Also referred to as a cortical desmoid, periosteal desmoid, or “tug lesion,” it is seen most commonly in young adolescents, with a slight preponderance in boys, with one-third occurring bilaterally. It is thought to be related to repeated microtrauma with pulling of the adductor magnus or medial gastrocnemius head. Proper treatment

 

involves recognition of this benign disorder without further work-up. Often best seen on an oblique radiograph, the lack of soft-tissue mass or bone destruction leads to the benign diagnosis. Serial radiographs may show complete resolution by age 20.

PREFERRED RESPONSE: 2- Observation and serial radiographs

 

CLINICAL SITUATION FOR QUESTIONS 84 THROUGH 86

Figures 84a and 84b are the CT and MRI scans of a 17-year-old girl with a painful lumbosacral scoliosis that has been present for 12 months. Examination is notable only for pain over the left sacral region and a postural scoliosis leaning away from this side.

 

 

Question 84 …The girl’s parents should be advised that their daughter’s condition

1. will respond to bracing and require treatment if curve magnitude exceeds 45 degrees at skeletal maturity.

2. results from a genetic mutation.

3. requires prolonged antibiotic treatment.

4. is likely to respond to percutaneous intervention.

 

Question 85 ..Medical treatment for this condition

1. uses nonsteroidal anti-inflammatory or aspirin medications.

2. uses radioactive iodine as first-line treatment.

3. centers on antimicrobial susceptibilities.

4. requires autologous stem cell transplantation.

 

Question 86 ..With treatment, the spinal deformity is expected to

1. spontaneously resolve.

2. remain stable and nonprogressive.

3. respond in proportion to the family’s compliance with brace treatment.

4. resolve in the coronal plane and progress in the sagittal plane.

 

DISCUSSION..This young woman has classic imaging features of a sacral ala osteoid osteoma. Preferred treatment is removal or ablation of the nidus by surgery or percutaneous techniques. Bracing may be used for adolescent idiopathic scoliosis, but plays no role in the treatment of scoliosis secondary to osteoid osteoma. Antibiotics would be used for osteomyelitis. There is no known genetic predisposition to osteoid osteoma.

Nonsteroidal medications or aspirin will alleviate symptoms in the short term. Antibiotics, radioactive iodine, and stem cell transplantation play no role in treatment for osteoid osteoma. The “scoliosis” is expected to resolve following treatment. Bracing is not needed. No lasting spinal deformity is expected.

PREFERRED RESPONSE: 4- is likely to respond to percutaneous intervention.

 

PREFERRED RESPONSE: 1- uses nonsteroidal anti-inflammatory or aspirin medications. PREFERRED RESPONSE: 1- spontaneously resolve.

 

Question 87 ..Figures 87a through 87e are the radiograph, MRI scans, and biopsy specimen of an 83-year-old woman who is experiencing pain in her distal thigh with activity and at night. She has undergone total hip arthroplasty for hip osteoarthritis. The most appropriate treatment is

 

 

 

1. external beam radiation.

2. curetting and cementation.

3. radiofrequency ablation.

4. wide local resection.

 

DISCUSSION..The imaging shows a cartilaginous lesion with destruction and a malignant extraosseous mass most consistent with a dedifferentiated chondrosarcoma. The histology demonstrates a high-grade spindle-cell sarcoma abutting a cartilaginous tumor, confirming this diagnosis. Treatment in this patient would be wide resection. The role of

chemotherapy in this tumor is unproven, and an 85-year-old patient is an unlikely candidate for such treatment. Radiofrequency ablation, curettage, and radiation do not play a role in the treatment of this tumor.

PREFERRED RESPONSE: 4- wide local resection.

 

CLINICAL SITUATION FOR QUESTIONS 88 through 92

Figures 88a and 88b are the radiographs of a 70-year-old woman with a remote history of localized renal cell carcinoma. She has insidious onset of right shoulder pain that worsens with any activity and at night. She appears otherwise healthy.

 

 

Question 88 ..The next treatment step is

1. radiotherapy.

2. CT scan of the chest, abdomen, and pelvis.

3. bone marrow biopsy.

4. surgical stabilization.

 

Question 89..What is the role of presurgical lesional biopsy for this patient?

1. Unnecessary, considering the known history of renal cell carcinoma

2. Should be performed before any surgical treatment

3. Should be performed if the lesion is solitary, but not necessarily if multifocal

4. Should always be accompanied by bone marrow biopsy

 

Question 90 ..Representative histology is shown in Figure 88c. Advanced imaging shows mild extraosseous extent of disease, nondisplaced pathologic fracture, and no neurovascular encasement. The humerus is best managed with

1. radiotherapy.

2. closed intramedullary rodding.

3. curettage, cancellous allograft, and plate fixation.

4. resection and reconstruction.

 

Question 91 ..Chemotherapeutic treatment for this patient

1. centers on bone marrow transplantation.

2. has severe myelosuppressive effects.

3. inhibits vascular endothelial growth factor (VEGF) pathways.

4. is given as a radiation sensitizer.

 

Question 92 ..Oncologic outcome for this patient

1. is influenced by extraosseous tumor extension.

2. is more favorable if the lesion is solitary.

3. involves a predictable rapid demise.

4. hinges on the presence or absence of gene amplification.

 

DISCUSSION…This patient has a lytic lesion filling the proximal humerus with a history of renal cell carcinoma. In a patient with a history of localized cancer with a bone lesion, staging with CT scan of the chest, abdomen, and pelvis (and a bone scan, as well) is indicated to define the extent of disease. A positron emission tomography scan, not given as an option, would be a reasonable substitute for a CT and bone scan. The most likely clinical scenario is the development of metastatic renal cell carcinoma, and these tests will define the extent of disease. Immediate radiotherapy would not be indicated without a diagnosis; as well, renal cell carcinoma’s response to radiotherapy is unpredictable, and the extent of bony destruction implies a degree of mechanical insufficiency that would benefit from surgical treatment. Bone marrow biopsy would be indicated for hematopoietic tumors such as myeloma or lymphoma. Reflexive surgery should be avoided until a diagnosis is obtained or a widespread metastatic process is identified to avoid inadvertently mistreating a new sarcoma. As well, curettage procedures near joints are not very durable in renal cell carcinoma because of its aggressive behavior and radioresistance.

Biopsy generally is not necessary for patients with established metastatic disease and typical presentations prior to surgical management. Additionally, if a patient has new metastatic disease and multiple lesions, biopsy is not needed before surgery because histologic confirmation can be obtained at surgery. However, for a patient with a solitary lesion and no history of metastatic disease, biopsy is indicated to exclude a new primary tumor before surgical treatment is undertaken.

The histology reveals clear-cell carcinoma consistent with a renal primary. Radiotherapy alone is a poor option considering the unpredictable response of renal cell carcinoma to radiation and the presence of a pathologic fracture. Closed intramedullary rodding would provide little proximal fixation. Both this option and curettage are not optimal because of significant bleeding and lack of durability in this situation. Amputation is seldom indicated for metastatic disease (even if the neurovascular bundle is encased, which it is not). Formal resection and reconstruction provides the most durable functional outcome. For a solitary lesion, resection of the entire lesion would be preferable, although in other situations, intralesional resection and prosthetic reconstruction may be applicable. If an intralesional procedure is planned, embolization should be considered before surgery.

Recent understanding of the role of the VEGF pathway in renal cell carcinoma has led to the use of tyrosine kinase inhibitors and related agents for chemotherapy. These can have wound-healing effects (critical for surgeons to recognize and understand), but generally are not myelosuppressive. Objective response rates approach 30%. Bone marrow transplantation and radiosensitizing chemotherapy are not used in this situation.

Patients with metastatic renal cell carcinoma to bone have a median survival of 11.5 months in the largest study, and this likely improves with newer adjuvant therapies. Patients with solitary lesions have longer survival, but the likelihood of true cure is low even with en bloc resection. There is no known prognostic significance of extraosseous extension or gene amplification in renal carcinoma.

 

PREFERRED RESPONSE: 2- CT scan of the chest, abdomen, and pelvis.

PREFERRED RES: 3- Should be performed if the lesion is solitary, but not necessarily if multifocal PREFERRED RESPONSE: 4- resection and reconstruction.

PREFERRED RESPONSE: 3- inhibits vascular endothelial growth factor (VEGF) pathways. PREFERRED RESPONSE: 2- is more favorable if the lesion is solitary.

 

Question 93 ..Figures 93a and 93b are the MRI scans of a 24-year-old man with painless, persistent swelling in his left knee without any trauma. What is the best next treatment step?

 

 

1. Arthroscopic anterior synovectomy and posterior open resection

2. Arthroscopic anterior synovectomy only

3. Radiation therapy and wide excision

4. Observation

 

DISCUSSION..The lesion seen in the figures is pigmented villonodular synovitis (PVNS), as shown by the dark areas on MRI scan attributable to chronic hemosiderin deposition. The age of the patient, symptom of persistent swelling, and lack of trauma are all consistent with a synovial proliferative disorder. The fronds arising from the synovium make PVNS the most likely of the synovial proliferative diseases, which include PVNS, synovial chondromatosis, lipoma arborescens, and synovial hemangioma. The imaging shows diffuse disease throughout the knee in the anterior compartment and extra-articular disease extending from the posterior compartment. The current accepted standard of care for initial presentation and treatment is an anterior synovectomy and an open posterior approach to resect the extra-articular disease. Recurrence rates for diffuse disease are higher with arthroscopic compared to open synovectomy, although morbidity is lower with arthroscopic treatment. Radiation therapy and wide excision would be reserved for a soft-tissue sarcoma, and, in the setting of a chronic effusion, observation would not suffice because the joint is at risk for degradation from the chronic hemosiderin and inflammatory reaction in the intra-articular space.

PREFERRED RESPONSE: 1- Arthroscopic anterior synovectomy and posterior open resection

 

Question 94 ..What biopsy technique for a posterior thigh sarcoma is associated with the highest risk for adverse outcome?

1. Transverse incision open biopsy

2. Core needle biopsy

3. Fine-needle aspirate

4. Longitudinal incision open biopsy

 

DISCUSSION..Fundamental planning and execution of a biopsy are imperative to maximize a surgeon’s technical ability to perform limb-salvage surgery and preclude risk for amputation as a result of a poorly executed biopsy. An incorrectly performed biopsy can place a patient who is a limb-salvage candidate into a non-limb-salvage category. Transverse incisions for a sarcoma on an extremity are absolutely contraindicated. A transverse incision increases the extent of dissection

 

necessary to achieve an appropriate radical resection, contaminates more anatomic planes, and places neurovascular structures at higher risk for contamination. In many instances, a free vascularized muscle flap and/or skin grafting is needed to close the defect created by an incorrectly performed biopsy. Meticulous hemostasis at the time of biopsy is also essential to avoid contamination of additional tissue, thus expanding the extent of dissection.

For open biopsies, incisions in line with the long axis of a limb are mandatory. Many tumors are amenable to core needle biopsy. Placement of the needle or incision must be carefully thought out to ensure that the biopsy tract may be excised in continuity with the mass at the time of definitive resection surgery. In an ideal situation, the biopsy should be performed by the surgeon, who will perform the definitive procedure. This obviates the need to speculate about needle tracts and biopsy techniques. Fine-needle aspirate biopsies are generally safe, but likely have lower diagnostic yield. PREFERRED RESPONSE: 1- Transverse incision open biopsy

 

Question 95 ..A 60-year-old woman with a history of breast cancer has a rapidly enlarging arm mass. The lesion is situated outside of the prior irradiation field, but within an area of heavy lymphedema involvement. Needle biopsy reveals a high-grade sarcoma. What is the most likely diagnosis?

1. Lymphangiosarcoma

2. Acral myxoinflammatory fibroblastic sarcoma

3. Hemangioendothelioma

4. Hemangiopericytoma

 

DISCUSSION..Lymphangiosarcomas that arise in pre-existing lymphedema are aggressive malignancies (ie, Stewart-Treves syndrome) that require resection or amputation. Acral myxoinflammatory fibroblastic sarcoma is a low-grade sarcoma. Hemangioendothelioma and hemangiopericytoma are not typically associated with chronic lymphedema.

PREFERRED RESPONSE: 1- Lymphangiosarcoma

 

RESPONSES FOR QUESTIONS 96 THROUGH 100

1. Osteosarcoma

2. Ewing sarcoma

3. Langerhans cell histiocytosis (LCH)

4. Osteomyelitis

5. Primary lymphoma of bone

Match the condition above to the patient description below.

 

 

 

Question 96..10-year-old girl with sickle cell anemia and a swollen, erythematous, and painful elbow (Figures 96a through 96d)

Question 97 …12-year-old girl with knee and lower leg pain and swelling for 2 months after minor trauma (Figures 97a through 97f)

 

 

Question 98 ..11-year-old boy with severe pain in the lower back and pelvic region, particularly with activity and at night; CD99 immunostaining positive (Figures 98a through 98e)

 

 

 

Question 99…4-year-old boy who began limping after having increasing pain in his lower thigh and knee for 3 months

 

 

 

Question 100 …22-year-old man with rapidly growing mass and severe swelling in the knee; CD20-positive on immunostaining (Figures 100a through 100f)

 

 

 

 

 

 

DISCUSSION…Osteomyelitis in the pediatric population occurs in approximately 1 in 5000 children. Staphylococcus aureus accounts for approximately 80% of all infections. Staphylococcus remains the most common organism in patients with sickle cell anemia; however, an unusual culprit in these patients can be salmonella. Imaging studies may not be specific but often show periosteal reaction, variable bone loss and production, and significant inflammation on MRI scan. The classic sign on radiograph is “bone-in-bone” for subacute and chronic cases. This often signifies new bone (involucrum) surrounding the necrotic “trapped” sequestrum. The histopathology varies depending on the acuity of disease. A variety of inflammatory cells often will be seen. Typically, more neutrophils are seen in acute disease, and lymphocytes and macrophages in chronic disease. Chronic cases normally show focal areas of bone necrosis with empty lacunae.

Osteosarcoma is the most common primary cancer of bone excluding multiple myeloma. It most often occurs during the first 2 decades of life. The imaging studies show an aggressive bone loss and new bone formation process in addition to a soft-tissue mass on MRI scan. In this case, the radiograph shows an excellent example of a “sunburst” or “hair-on-end” pattern signifying the rapid growth of the tumor and subsequent periosteal reaction. The histopathology varies by subtype; however, the most common variety (classic, high grade) as in this scenario demonstrates hypercellular round or spindle cells with atypia, pleomorphism, atypical mitoses, and osteoid production. Ewing sarcoma is the second-most-common bone sarcoma in children. It will demonstrate aggressive changes on radiograph, but, unlike osteosarcoma, it frequently does not produce new bone within the matrix of the tumor. However, periosteal elevation and bone reaction are often seen. This case shows subtle changes on radiograph but impressive changes on MRI scan with a soft-tissue mass and extensive bone marrow involvement. This is fairly common for small round blue-cell tumors such as Ewing sarcoma/primitive neuroectodermal tumor, lymphoma, multiple myeloma, and others. The histopathology often shows hypercellularity with sheets of small round blue cells. In most cases, CD99 is positive and a characteristic 11:22 translocation is seen, making the diagnosis definitive.

LCH is a rare condition with an uncertain pathogenesis. It is generally seen in patients younger than 20 years of age and often can mimic other conditions such as infection or cancer. The imaging studies can range from benign-looking with a focal, well-circumscribed lesion to more common aggressive lesions with less-defined borders, periosteal reaction, associated edema, and, in some cases, pathologic fracture. The histopathology in this case is critical to the diagnosis. The presence of Langerhans cells in a granulomatous-like setting with a reactive background of macrophages, eosinophils, multinucleate giant cells, and T cells is important to identify. The Langerhans cell is a large, ovoid, mononuclear cell with a folded nucleus, a discrete nucleolus, and

 

moderate amounts of slightly eosinophilic homogeneous cytoplasm. On electron microscopy, Birbeck granules with their tennis racquet form can be seen in Langerhans cells. Primary lymphoma of bone is rare. It accounts for approximately 1% of all lymphoma cases. As with other small round blue-cell tumors, the imaging may vary. Osteolytic and osteoblastic findings may be present on radiograph, but often the MRI scan reveals a larger-than-expected soft-tissue component. The histopathology shows sheets of small round blue cells. These can be differentiated from others in this category by flow cytometry and also by using specialized surface markers like CD20, as in this case.

PREFERRED RESPONSE 96..: 4- Osteomyelitis

PREFERRED RESPONSE 97 …: 1- Osteosarcoma PREFERRED RESPONSE 98…: 2- Ewing sarcoma

PREFERRED RESPONSE 99..: 3- Langerhans cell histiocytosis (LCH) PREFERRED RESPONSE 100..: 5- Primary lymphoma of bone

 

RESPONSES FOR QUESTIONS 101 THROUGH 104

1. Clear cell renal carcinoma

2. Squamous carcinoma of the lung

3. Multiple myeloma

4. Metastatic adenocarcinoma

Match each set of photomicrographs with the correct diagnosis.

Question 101 ..Figures 101a and 101b

 

 

PREFERRED RESPONSE: 1- Clear cell renal carcinoma

Question 102 ….Figures 102a and 102b

 

 

 

PREFERRED RESPONSE: 4- Metastatic adenocarcinoma

Question 103 ..Figures 103a and 103b

 

 

PREFERRED RESPONSE: 2- Squamous carcinoma of the lung

 

Question 104 ..Figures 104a and 104b

 

 

 

PREFERRED RESPONSE: 3- Multiple myeloma

 

DISCUSSION..These photomicrographs represent metastatic entities commonly found in the bone. Renal carcinoma is distinguished by large cells with vacuolated cytoplasm that warrant the term "clear cell" carcinoma. Squamous carcinomas are characterized by nests of epithelial cells that are relatively monotonous and form layers or sheets of cells. Myeloma is a plasma cell proliferative disorder, and the cells are classified by the "clock-face" nuclei and basophilic cytoplasm.

Adenocarcinomas are noted to have the appearance of malignant cells forming gland-like structures in the invaded tissue. The more well-differentiated the tumor, the more prominent and distinctive are the glands. These representations are relatively classic for lesions such as prostate and breast adenocarcinoma.

 

Question 105 ..A 22-year-old mother noticed left leg pain while lifting her only child. A previous biopsy of her left tibia 7 years ago had been interpreted as osteofibrous dysplasia. She has no other medical history. Her current anteroposterior and lateral radiographs are shown in Figures 105a and 105b. Her comparative T2-weighted axial MRI scan from a similar area of the diaphyseal tibia is shown in Figure 105c. The histologic specimens are shown in Figures 105d and 105e. A cytokeratin stain is shown in Figure 105f. The diagnosis is

 

 

1. osteofibrous dysplasia.

2. osteofibrous dysplasia-like adamantinoma.

3. low-grade osteosarcoma.

4. metastatic adenocarcinoma.

 

DISCUSSION…An insidious onset of pain is a characteristic symptom in patients with

adamantinoma. The characteristic radiographic finding is a “soap-bubble” osteolytic lesion of the tibia with surrounding sclerosis. A soft-tissue mass also is characteristic. Few keratin-positive cells are seen in osteofibrous dysplasia. The characteristic fibrous stroma with spicules of bone with basophilic epithelioid cells is diagnostic of adamantinoma. The other diagnoses mentioned do not have these characteristics. PREFERRED RES: 2- osteofibrous dysplasia-like adamantinoma.

 

Question 106 ..Figures 106a and 106b are the T1 sagittal and T2 coronal images of a 41-year-old woman who has been experiencing electric shock-type radiating pain over her right ankle for 4½ years. Her biopsy specimen is shown in Figure 106c. What is the best next treatment step?

1. Marginal excision

2. Wide excision

3. Wide excision and radiation

4. Observation

 

 

 

 

DISCUSSION…The lesion seen here is a benign nerve sheath tumor—specifically, a schwannoma. The diagnosis of neurogenic tumors can be suggested from their imaging appearance, including lesion shape and intrinsic imaging characteristics such as target and string signs. The histology shows benign nerve elements including verocay bodies with Antoni A (more cellular) and Antoni B (less cellular) areas. Most patients with benign nerve sheath tumors present with a painful mass, paresthesias, or numbness without significant weakness. Marginal excision with preservation of the associated nerve fibers is the optimal treatment for symptomatic schwannomas. Wide excision eliminates symptoms successfully with minimal concern for recurrence, but should be avoided to preserve nerve function. Wide excision with or without radiation is not warranted in this benign condition, and, although observation is acceptable for difficult locations or asymptomatic Schwannomas, the persistent symptoms experienced by this patient preclude observation as the best option. PREFERRED RESPONSE: 1- Marginal excision

 

Question 107 ..Figures 107a through 107c are the radiograph, CT, and bone scan of a 68-year-old man. While walking, he collapsed and was unable to ambulate because of pain and deformity in his right leg. What is the most appropriate next step?

 

 

 

1. Staging studies to assess the extent of disease

2. Immediate stabilization of the fracture with an intramedullary nail

3. Curetting and bone culture

4. Segmental resection of the tibia and allograft reconstruction

 

DISCUSSION…This patient has a pathologic fracture; in patients older than age 50, the most likely diagnosis is metastatic carcinoma or hematopoietic malignancy. A systemic work-up with staging imaging studies and laboratory tests as outlined by Rougraff and associates will identify the primary site of disease in approximately 90% of patients. A biopsy may not be necessary, and this protocol will also effectively exclude a primary sarcoma in the vast majority of patients. The other options all initiate treatment without first evaluating for extent of disease and diagnosis. If this turns out to be a sarcoma, stabilization or curetting the lesion might make subsequent limb salvage difficult or impossible. Segmental resection adds unnecessary morbidity to the surgical procedure in the more common circumstance that this is revealed to be metastatic carcinoma.

PREFERRED RESPONSE: 1- Staging studies to assess the extent of disease

 

RESPONSES FOR QUESTIONS 108 THROUGH 111

1. Glomus tumor

2. Diffuse pigmented villonodular synovitis (PVNS)

3. Extra-abdominal fibromatosis

4. Schwannoma

5. Hemangioma

Please match the characteristics below to the condition listed above.

Question 108 ..Painful lesion that frequently is triggered by cold and has characteristics of vascular origin

 

Question 109 …High local recurrence rate despite surgical excision and controversial to treat with chemotherapy and/or external beam radiation; may have similar appearance as a soft-tissue sarcoma.

 

Question 110 ..S-100-positive and low recurrence rate after surgical excision

 

Question 111 ..Most common soft-tissue tumor in childhood and infancy; may fluctuate in size with activity

 

DISCUSSION..Hemangiomas are common soft-tissue tumors that resemble the architecture of normal blood vessels. They are the most common tumors seen during infancy and childhood and they can be found in any tissue type. Larger, deep hemangiomas commonly cause pain with activity. They may fluctuate in size and, if superficial enough, skin color changes may be noted.

PVNS is a locally aggressive proliferative disorder of the synovium. It can be found in the joint, tendon sheath, or synovial bursa. It generally is found in 2 forms: localized or nodular diffuse or villonodular. The diffuse form has a high local recurrence rate between 33% and 50%. The peak incidence is noted in people who are 20 to 50 years of age and it is more common in women.

Treatment is generally surgical, although radiation implants have been used for recalcitrant cases. A schwannoma (neurilemoma) is a common encapsulated nerve sheath tumor. Histologically, it has 2 components: Antoni A (cellular regions) and Antoni B (loose myxoid regions). Like most neural tumors, S-100 immunostain is strongly positive. As opposed to neurofibromas, which are intraneural and seen commonly in patients with neurofibromatosis type I, these lesions are located within the nerve sheath, more commonly occur as a solitary tumor, and are generally easier to remove than neurofibromas. However, there is risk for nerve damage with excision of any nerve

 

sheath tumor, and for difficult locations or asymptomatic Schwannomas, observation may be appropriate. The local recurrence rate is low with marginal excision.

Extra-abdominal fibromatosis (desmoid tumor) is locally aggressive and can be found superficially or deep. The deep variant tends to grow larger and faster. Local recurrence rates can be high, but vary greatly on location, size, and histology, among other factors. Surgical excision is the treatment of choice. External beam radiation and chemotherapy have been used in recurrent disease or to treat regions that are unresectable. In some cases, fibromatoses can mimic sarcomas, but these tumors do not have metastatic potential.

Glomus tumors are small, painful soft-tissue masses of smooth muscle origin typically in a subungual location. They often cause moderate to severe pain from touch or cold.

PREFERRED RESPONSE 108-: 1- Glomus tumor

PREFERRED RESPONSE 109-: 3- Extra-abdominal fibromatosis

PREFERRED RESPONSE 110-: 4- Schwannoma PREFERRED RESPONSE-111--: 5- Hemangioma

 

Question 112 ..Figures 112a and 112b are the anteroposterior and lateral radiographs of a 65-year-old man who has a significant history of tobacco abuse and a 6-week history of right thigh pain. Axial and sagittal MRI scans are seen in Figures 112c and 112d. His MR angiogram is shown in Figure 112e. A biopsy of a lesion is shown in Figure 112f. What is the most likely diagnosis?

 

 

1. Secondary sarcoma in a pre-existing condition

2. Angiosarcoma

3. Metastatic lung carcinoma

4. Fibrous dysplasia

 

DISCUSSION…The figures show an aggressive destructive lesion in a bone that is already involved with Paget disease, and the pathology shows highly malignant cells. This represents a secondary sarcoma arising in Pagetoid bone. Secondary sarcomas occurring in Pagetic bone include malignant fibrous histiocytoma and chondrosarcomas, but osteosarcomas are the most common malignancy in these patients. Most patients are older than age 60 and have new pain in the setting of known Paget disease. The prognosis is generally poor because this is a very aggressive sarcoma that is difficult to treat in an older population. Wide surgical removal and chemotherapy are most commonly employed. The pathology does not show rudimentary vessels or channels which are expected with angiosarcoma, effectively excluding that diagnosis. A lack of nests or gland formation excludes metastatic lung carcinoma, and the absence of fibrous stroma intermixed with bone islands or “Chinese characters” excludes fibrous dysplasia.

PREFERRED RESPONSE: 1- Secondary sarcoma in a pre-existing condition

 

CLINICAL SITUATION FOR QUESTIONS 113 THROUGH 116

Figures 113a and 113b are the radiographs of a 68-year-old-man who has increasing pain in his left groin with weight-bearing activities and a Trendelenburg gait. Radiographs reveal a lytic lesion of the greater trochanter. An initial diagnosis of adenocarcinoma of the lung was made 1 year before this presentation. His lung cancer treatment consisted of partial lobectomy and postsurgical radiation therapy.

 

 

Question 113 ..What is the preferred study to stage his disease at this time?

1. Whole-body bone scan

2. Chest/abdomen/pelvis CT scan

3. Bronchoscopy

4. Positron emission tomography (PET) scan

 

Question 114 ..If this is a solitary metastasis, what is the preferred treatment?

1. Radiation therapy

2. Chemotherapy

3. Curettage, cementation, and internal fixation

4. Resection and prosthetic reconstruction

 

Question 115 ..Before receiving treatment, the patient falls and sustains a fracture through the base of the femoral neck region; the best treatment now is

1. radiation therapy.

2. chemotherapy.

3. curettage, cementation, and internal fixation.

4. resection and prosthetic reconstruction.

 

Question 116 ..Staging studies show no other lesions and surgical treatment is planned; when should a biopsy be performed?

1. Before surgery

2. Intraoperatively after instrumentation

3. After surgery (reamings/curettings sent)

4. No biopsy is needed

 

DISCUSSION…Patients with a metastatic lung carcinoma are best staged and imaged with a PET scan. Although many tumors are clinically evaluated with PET scans, metastatic lung cancer is one of the few “approved” indications for PET imaging. This imaging modality is sensitive for delineating the extent of disease and helpful for identifying areas that may also be at risk for pathologic fracture. Stabilization of painful, lytic lesions in weight-bearing bones is recommended to prevent pathologic fracture. Stabilization of an impending pathologic fracture is generally easier than stabilization of a pathologic fracture; once the patient in this vignette sustains a fracture, resection and reconstruction is indicated because stabilization alone is unlikely to heal and poses high risk for failure. In cases of extreme bone loss, especially in the epiphyseal region, reconstruction with tumor megaprostheses is desirable to avoid mechanical failure of additional internal fixation. Patients with widely metastatic disease may not be able to use ambulatory assistance aids effectively, placing traditional internal fixation at risk for failure. Use of megaprostheses obviates the need for adjuvant therapies to correct the loss of bone stock.

Radiation therapy alone to lesions that are radiosensitive is effective but does not alleviate the risk for pathologic fracture. Chemotherapy alone is insufficient treatment for bone metastases.

Hormonal therapy is acceptable for treatment of hormone-sensitive tumors; however, is not sufficient treatment for an impending pathologic fracture.

For patients with remote diagnoses of carcinoma, biopsy of new-onset presumed metastases is mandatory to avoid an incorrect treatment regimen being employed. Patients can develop a secondary malignancy or infection, both of which will require a different treatment regimen. Biopsy should be done and diagnosis established either preoperatively or intraoperatively prior to instrumentation (with frozen section analysis) to avoid contamination of the femoral canal and soft-tissue envelope. Sending a specimen after instrumenting the femur or after surgery contaminates the femur if a sarcoma is diagnosed and lessens the likelihood of limb salvage.

 

PREFERRED RESPONSE: 4- Positron emission tomography (PET) scan PREFERRED RESPONSE: 3- Curettage, cementation, and internal fixation PREFERRED RESPONSE: 4- resection and prosthetic reconstruction.

PREFERRED RESPONSE: 1- Before surgery

 

CLINICAL SITUATION FOR QUESTIONS 117 THROUGH 120

Figures 117a through 117c are the radiographs and MRI scan of a 16-year-old boy who has had a persistent fullness in his thigh since being kicked while playing soccer 4 weeks ago. He states that initially the area was painful, but now all symptoms other than the mass have resolved.

 

 

 

 

 

 

Question 117 …What is the most likely diagnosis?

1. Myositis ossificans

2. Juxtacortical osteogenic sarcoma

3. Osteochondroma

4. Cortical desmoid

 

Question 118 ..You explain to the patient and his parents that the lesion is

1. benign and simply can be observed with serial radiographs.

2. posttraumatic and should be allowed to mature prior to excision.

3. premalignant and should be immediately excised.

4. malignant and should be resected following neoadjuvant chemotherapy.

 

Question 119 ..A reliable indicator for the presence of malignancy in this scenario would be

1. loss of heterozygosity of the EXT-1 gene.

2. occurrence in a skeletally immature individual.

3. a cartilage cap of 1 cm.

4. growth beyond skeletal maturity.

 

Question 120 Findings of multiple lesions in multiple skeletal sites may be associated with

1. decreased risk for malignancy.

2. a characteristic chromosomal translocation.

3. soft-tissue hemangiomas.

4. limb deformity and short stature.

 

DISCUSSION..This lesion is an osteochondroma. The finding on MRI scan or CT scan of a shared cortex between the lesion and the host bone is pathognomonic. These lesions are benign and most often can be followed with serial radiographs. Reasons to excise would be pain, unacceptable cosmetic deformity, or growth, particularly if the patient is beyond skeletal maturity, which can be a sign of malignancy. Loss of heterozygosity of either the EXT-1 locus or EXT-2 locus is associated with hereditary multiple exostoses (HME), which increases the risk for malignant degeneration of 1 or more lesions throughout a patient’s life but does not always lead to malignancy. Because HME affects all growth plates to some degree, short stature and limb deformity may occur. A cartilage cap of up to 2 cm can be acceptable, particularly during youth. If, however, this condition persists or enlarges beyond skeletal maturity, excision should be entertained……PREFERRED RESPONSE: 3- Osteochondroma

PREFERRED RESPONSE: 1- benign and simply can be observed with serial radiographs. PREFERRED RESPONSE: 4- growth beyond skeletal maturity.

PREFERRED RESPONSE: 4- limb deformity and short stature.

 

Question 121 ..Figure 121a is the axial T1 MRI scan and Figure 121b is the coronal T1 MRI scan of an 85-year-old man who has a mass in his medial thigh. The mass was present for years and recently grew. His biopsy specimen is shown in Figure 121c. What is the best treatment for this patient?

 

 

1. Chemotherapy and wide local resection

2. Wide local resection and radiotherapy

3. Marginal excision

4. Observation and reimaging in 6 months

 

DISCUSSION….The history of a long-standing mass with sudden growth suggests transformation of an existing tumor. The imaging features of a fatty lesion with internal complexity suggest an atypical lipomatous tumor (formerly called a well-differentiated liposarcoma). Juxtaposed to this on imaging is a solid tumor. Histology reveals a high-grade spindle-cell sarcoma adjacent to a fatty tumor. This clinical presentation is most consistent with a long-standing atypical lipomatous tumor that has undergone dedifferentiation. The role of chemotherapy for soft-tissue sarcomas is controversial and unlikely to be applicable in an 85-year-old man. However, wide local excision with adjuvant radiation therapy is the best option for durable local control. Marginal excision would be appropriate for an atypical lipomatous tumor that has not undergone dedifferentiation.

Observation of a high-grade sarcoma is not appropriate. PREFERRED RESPONSE: 2- Wide local resection and radiotherapy

 

Question 122 ..What tumor commonly metastasizes to regional lymph nodes?

1. Fibromyxoid sarcoma

2. Epithelioid sarcoma

3. Leiomyosarcoma

4. Liposarcoma

 

DISCUSSION…The common sarcomas that metastasize to regional lymph nodes are epithelioid sarcoma, synovial sarcoma, angiosarcoma, rhabdomyosarcoma, and clear cell sarcoma.

Metastasis to the lungs remains the most common location for all sarcoma metastases. Daigeler and associates evaluated regional lymph node metastasis (RLNM) and reported that the condition was seen in 21.4% of patients with epithelioid sarcoma and 17.6% of patients with clear cell sarcoma. Other sarcomas had RLNM rates below 10%.

PREFERRED RESPONSE: 2- Epithelioid sarcoma

 

Question 123 ..A 64-year-old woman has significant right arm pain associated with a destructive proximal humeral bone lesion with an associated soft-tissue mass. Her medical history includes carcinoma of the breast treated 8 years ago with modified radical mastectomy, hormone receptor-based chemotherapy, and 45 Gy of radiation with 8 subsequent disease-free years. Biopsy reveals a high-grade osteogenic sarcoma. What factor is most likely related to her current disease?

 

1. Presence of metastatic disease

2. Dosage of radiation treatment

3. Type of prior surgical procedure

4. Type of chemotherapy given

 

DISCUSSION…Postradiation sarcomas are a rare subset of sarcomas (approximately 3% of all sarcomas), with an incidence lower than 1% in patients receiving high-dose radiation. Diagnosis is usually based on the following: differing histologic diagnoses between original and secondary lesion, location within the field of radiation, latent period of more than 4 years, and radiation doses higher than 40 Gy (although this level is controversial and no true threshold exists). Chemotherapy is not related to postradiation sarcoma because the ionizing effect of the radiation causes irreparable cell damage, leading to possible transformation in the future to malignancies. Five-year survival from postradiation sarcoma is approximately 33%. Complete surgical resection is the mainstay of treatment, with adjunctive chemotherapy used in bone sarcomas or metastatic disease. Neither type of surgical procedure nor chemotherapy has an impact on the development of postradiation sarcoma. PREFERRED RESPONSE: 2- Dosage of radiation treatment

 

Question 124 ..Figures 124a and 124b are the MRI scans of a 25-year-old woman who has a painful mass in her left gluteal and thigh region. Her biopsy specimen is seen in Figure 124c. What is the most likely diagnosis?

 

 

1. Desmoid fibromatosis

2. Extraskeletal Ewing sarcoma

3. Metastatic breast cancer

4. Lymphoma

 

DISCUSSION..The imaging shows an infiltrative soft-tissue mass; histology demonstrates a bland spindle-cell lesion without nuclear atypia consistent with desmoid tumor. Extraskeletal Ewing sarcoma would be expected to have more surrounding edema and small round blue cells on histology. Metastatic breast cancer and lymphoma can have similar appearances on MRI scan but

 

different characteristic histologies, the former with nests of malignant cells, and the latter with small round blue cells. PREFERRED RESPONSE: 1- Desmoid fibromatosis

 

CLINICAL SITUATION FOR QUESTIONS 125 THROUGH 128

A 45-year-old woman has increasing knee pain with activity and at rest. Her radiograph, MRI scan, and histology are shown in Figures 125a through 125c.

 

 

Question 125 ..The best descriptor for the lesion seen in Figures 125a and 125b is

1. malignant.

2. benign.

3. benign aggressive.

4. inflammatory.

 

Question 126 ..The next appropriate step in staging is

1. biopsy.

2. skeletal survey.

3. whole-body bone scan

4. chest radiograph.

 

Question 127 ..Biopsy results are shown in Figure 125c. Treatment should consist of

1. extended intralesional curettage.

2. chemotherapy and intralesional resection.

3. chemotherapy and complete resection.

4. radiation and complete resection.

 

Question 128..The cell that directly causes osteolysis in this lesion is

1. giant cell.

2. stromal cell.

3. osteoblast.

4. fibroblast.

 

DISCUSSION..This patient has a giant-cell tumor (GCT) of bone, a benign aggressive lesion. The lesion is locally aggressive and destroys bone, but metastasizes rarely enough to be considered benign. The metastatic rate of GCT is 5% or lower, and the metastatic disease most commonly

 

deposits in the lung, leading to the necessity for systemic staging of the chest. The histology of a GCT shows large, multinucleated giant cells in a field of smaller stromal cells similar to the nuclei of the giant cells. The osteoclast-like giant cells are directed through the receptor activator of nuclear factor kappa-beta ligand pathway to induce lytic bone destruction seen in this tumor, but the stromal cells are the neoplastic component. The preferred treatment is complete extended intralesional curettage with high-speed burring and bone grafting or cementation and fixation as individualized by patient and lesion.

PREFERRED RESPONSE: 3- benign aggressive. PREFERRED RESPONSE: 4- chest radiograph.

PREFERRED RESPONSE: 1- extended intralesional curettage. PREFERRED RESPONSE: 1- giant cell.

 

Question 129 ..Figures 129a through 129c are the lateral radiograph of the sacrum, axial CT scan, and a high-power view of a fine-needle biopsy of a 47-year-old man who has buttock pain and constipation. A large mass is palpable on rectal examination. The tumor cell that is the signature of this tumor is known as a(n)

 

 

1. giant cell.

2. physaliferous cell.

3. chondroblast.

4. adipocyte.

 

DISCUSSION…The lateral radiograph and axial CT scan image of the sacrum reveal a destructive lesion in S4 with a large soft-tissue mass. The differential includes chordoma, giant-cell tumor, and sacral schwannoma. The images and histology are consistent with chordoma, a tumor usually diagnosed during the fourth to eighth decades of life. The signature cell of the chordoma is the physaliphorous cell, although these cells are not pathognomonic of chordoma. Other types of tumors may have similar-appearing cells, and some chordomas may lack them. Physaliphorous cells have a large single cytoplasmic vacuole that causes them to appear like adipocytes. The extracellular stroma is myxoid, resembling chondrosarcoma.

PREFERRED RESPONSE: 2- physaliferous cell.

 

Question 130 ..Figures 130a through 130c show the CT scan and T1- and T2-weighted MRI scan sequences of an otherwise healthy 67-year-old woman with progressive left groin pain. Her biopsy specimen is shown in Figure 130d. Staging studies reveal no other lesions. Treatment should include

1. radiotherapy.

2. chemotherapy followed by surgical resection.

3. curettage with adjuvant treatment and grafting.

4. en bloc resection.

 

 

 

DISCUSSION…The imaging studies reveal a pelvic chondrosarcoma with extraosseous extension, which is confirmed by the biopsy specimen. En bloc resection is the treatment of choice for pelvic chondrosarcomas. Although curettage may be used for select low-grade extremity lesions, it is not recommended for pelvic lesions. As well, the imaging shows extraosseous extension and the histology shows a higher-grade lesion (characteristics that make curettage unsuitable in any skeletal location). Radiotherapy and chemotherapy do not play a role in nonmetastatic chondrosarcoma. PREFERRED RESPONSE: 4- en bloc resection.

 

Question 131 ..A lateral radiograph (Figure 131a), sagittal short tau inversion recovery MRI scan (Figure 131b), and an axial T1 contrast MRI scan (Figure 131c) were performed on a 15-year-old boy who has injured his right knee twice during the last 5 months. He has a reduced range of motion of the knee and posterior thigh tenderness. A biopsy showed bland spindle cells, giant cells, and blood-filled spaces without endothelial lining. What is the most appropriate treatment?

 

 

 

 

1. Chemotherapy and wide local excision

2. Chemotherapy and radiotherapy

3. Marginal excision

4. Extended intralesional curettage

 

DISCUSSION..The imaging shows an aneurysmal bone cyst with a destructive, eccentric metaphyseal lesion with fluid-fluid levels on MR imaging. The described histology confirms this. The differential diagnosis would include telangiectactic osteosarcoma, although there is no associated soft-tissue mass on imaging and no malignant stroma described on histology.

Treatment is extended intralesional curettage. Serial embolization is used in surgically inaccessible spaces. Chemotherapy and/or radiotherapy are not indicated for this benign lesion. Intralesional treatment rather than excision is the appropriate surgical option.

PREFERRED RESPONSE: 4- Extended intralesional curettage

 

CLINICAL SITUATION FOR QUESTIONS 132 THROUGH 134

 

 

Figure 132 is the bone scan of a 73-year-old man who is referred from his family doctor with diffuse bone pain, fatigue, and right knee pain. Examination is notable for pain with motion about the right knee and mild hyporeflexia.

 

Question 132 ..The most appropriate next step is

1. total spine MRI scan.

2. needle biopsy of the osseous lesion.

3. bone marrow biopsy.

4. CT scan of the chest, abdomen, and pelvis and laboratory studies

 

Question 133 ..During the course of evaluation, the patient develops a worsening mental status bordering on stupor. His serum calcium level is

15.8 mg/dL (reference range, 8.5-10.1mg/dL). Treatment should include

1. initiation of outpatient hemodialysis.

2. cardiac monitoring and fluid restriction.

3. intravenous bisphosphonate treatment.

4. intravenous vitamin D therapy.

 

Question 134 ..Further imaging shows pulmonary metastases without an obvious primary tumor of origin and an incomplete fracture of the right distal femur. A decision is made to surgically treat his distal femur fracture. What is the role of establishing a preoperative histologic diagnosis for this patient?

 

1. The distal femoral lesion should undergo needle biopsy first.

2. Bone marrow biopsy should be done first.

3. Preoperative biopsy is not necessary because a metastatic process is present.

4. Biopsy is not necessary if the lesion demonstrates a standardized uptake value (SUV) greater than 3 on fluorodeoxyglucose positron emission tomography (PET) imaging.

.

DISCUSSION…This patient has widespread metastatic disease based on bone scan findings. According to a study by Rougraff and associates, CT scan of the chest, abdomen, and pelvis and laboratory studies will identify the primary site of disease in more than 85% of cases. When signs or symptoms of spinal cord compression are absent, total spine MR imaging probably is not needed. Biopsy alone is less accurate than staging in establishing a diagnosis. Bone marrow biopsy is used only if a hematopoietic tumor (myeloma, lymphoma) is diagnosed.

 

Patients who develop hypercalcemia need hydration (with supplemental furosemide), bisphosphonates, and evaluation for cardiac arrhythmia. Hemodialysis and vitamin D therapy are not indicated, and fluid restriction would be contraindicated.

Biopsy before intervention for pathologic lower-extremity fracture likely is not needed in a scenario with numerous bone lesions and pulmonary metastases. The absence of a clear primary tumor of origin suggests this is unlikely to be a renal cell carcinoma for which preoperative embolization would be considered before an intralesional procedure. Tissue should be obtained at the time of surgery. Although an SUV greater than 3 is suspicious for malignancy, activity on PET scan should not influence the need for biopsy in this scenario.

PREFERRED RESPONSE: 4- CT scan of the chest, abdomen, and pelvis and laboratory studies. PREFERRED RESPONSE: 3- intravenous bisphosphonate treatment.

PREFERRED RESPONSE: 3- Preoperative biopsy is not necessary because a metastatic process is present

 

 

1- t(12;22)(q13;q12-3)

2- t(X;18)(p11.2;q11.2)

3- t(11;22)(q24;q12)

4- t(1;3)(p36.3;q25)

 

 

Question 135 ..Figures 135a through 135d are the radiographs, sagittal T1-, and coronal T2-weighted MRI scans of a 22-year-old woman who has had pain in her right ankle for 6 months. Figures 135e and 135f show a gross photograph of an amputated specimen and a biopsy specimen, respectively. In this tumor, cytogenetics reveals which translocation?

 

DISCUSSION..The radiographs and MRI scans reveal a multicentric destructive process. Multicentric lesions in adjacent bones suggest a vascular malignancy such as epithelioid hemangioendothelioma, which is now included under the category of solitary fibrous tumors. Here, the tumor cells are in cords within a myxoid stroma that resembles cartilaginous matrix. The translocation that occurs in epithelioid hemangioendothelioma is t(1;3)(p36.3;q25). Clear cell sarcoma has been shown to harbor t(12;22)(q13;q12-3), synovial sarcoma t(X;18)(p11.2;q11.2), and Ewing sarcoma t(11;22)(q24;q12).

PREFERRED RESPONSE: 4- t(1;3)(p36.3;q25)

 

Question 136 ..The optimal method to treat a recurrent presentation of pigmented villonodular synovitis (PVNS) with diffuse joint involvement in a 24-year-old woman with pain and symptomatic effusions is

1. 700 cGy of radiation therapy.

2. open arthrotomy with synovectomy.

3. imatinib therapy.

4. observation.

 

DISCUSSION..Local control of recurrent diffuse PVNS is best accomplished with open arthrotomy and complete synovectomy. Arthroscopic methods in the setting of persistent diffuse PVNS are associated with an unacceptably high rate of recurrence. Radiation therapy (700 cGy) is the typical dose administered for heterotopic ossification prophylaxis, but this dose is not high enough to achieve local control in PVNS. Imatinib, a colony-stimulating factor inhibitor, has been described for recurrent/refractory disease, but is not considered as effective as open surgical treatment.

PREFERRED RESPONSE: 2- open arthrotomy with synovectomy.

 

 

 

Question 137 ..The radiographs of a 63-year-old man with knee and proximal tibia discomfort are shown in Figures 137a and 137b. What genetic abnormality is associated with this condition?

 

1. Fibrillin mutation

2. EXT 1 gene

3. p53 mutation

4. t(x;18)

 

DISCUSSION..The radiographs reveal multiple osteochondromas consistent with multiple hereditary exostoses. The EXT 1 and EXT 2 genes have been associated with this condition. The EXT 1 gene is located at 8q24 and the EXT 2 gene at 11 p11-p12, but additional linkage to chromosomal locus 19p has suggested the existence of an as of yet unidentified EXT 3 gene.

Fibrillin mutations are associated with Marfan syndrome, p53 mutations with a variety of malignancies, and t(x;18) with synovial sarcoma. PREFERRED RESPONSE: 2- EXT 1 gene

 

RESPONSES FOR QUESTIONS 138 THROUGH 143

1. Multiple myeloma

2. Prostate cancer

3. Adenocarcinoma of the breast

4. Adenocarcinoma of the lung

5. Thyroid cancer

6. Renal cell carcinoma

Match the descriptions below to the conditions listed above.

Question 138 ..Often associated with the shortest mean survival once it is metastatic to bone and solid organs

 

Question 139 ..Advanced disease including bone metastases is treated with vascular endothelial growth factor (VEGF) inhibitors (ie, sunitinib) and, typically, the lesions are radioresistant.

 

Question 140 ..Often treated with bisphosphonates and radioiodine in the setting of metastatic bone disease

 

Question 141..Frequently involves mixed osteolytic and osteoblastic metastatic bone disease that typically is less responsive to treatment if the patient is human epidermal growth factor receptor 2 (HER-2)-positive

 

Question 142 ..Classically known for predominantly osteoblastic metastatic bone disease in male patients

 

Question 143 …A small round blue-cell neoplasm of plasma cells responsive to chemotherapy and radiation

 

DISCUSSION…Metastatic bone disease is a common phenomenon. The 5 most common primary cancers that spread to bone are breast, lung, thyroid, kidney, and prostate (commonly remembered with the easy pneumonic BLT with a Kosher Pickle). Radiologically, lung, thyroid, and kidney cancers are mostly radiolucent, prostate cancer classically shows osteoblastic changes, and breast cancer demonstrates a mix. Lung cancer in general is associated with the shortest mean survival among the primary carcinomas listed once the disease is metastatic to multiple locations including bone. Patients generally survive less than 1 year after diagnosis. Metastatic renal cell carcinoma has a

poor prognosis, but a small subset of patients can survive for years. Newer drugs such as VEGF inhibitors have shown in select cases to be effective, presumably by diminishing blood supply to these vascular tumors. These tumors are often radioresistant, making them difficult to control with nonsurgical measures. Thyroid cancer that has spread to bone is treated like most metastatic bone cancer. Bisphosphonates are used to help reduce bone pain and decrease risk for pathologic fracture. However, radioiodine is often used as targeted therapy. Prostate cancer that metastasizes to bone is best known for its classic osteoblastic lesions. However, it is important to note that this is not always the case. Whole-body bone scans often show intense uptake at the site of the metastatic lesions in patients with prostate cancer, as opposed to those with renal cell carcinoma or multiple myeloma, who often demonstrate little bony reaction and have a “cold” scan. Multiple myeloma is a primary cancer of the bone marrow. It is classified as a small round blue-cell tumor histopathologically and is generally responsive to chemotherapy and radiation. Metastatic breast cancer often features lesions that are mixed radiolucent and osteoblastic. The response to treatment is often dictated by tumor cell surface markers. Typically, the most responsive tumors

 

are estrogen and progesterone receptor positive and HER-2 negative. HER-2-positive tumors denote a more aggressive and difficult to treat subset of cancer.

 

PREFERRED RESPONSE 138..: 4- Adenocarcinoma of the lung PREFERRED RESPONSE 139…: 6- Renal cell carcinoma PREFERRED RESPONSE 140..: 5- Thyroid cancer

PREFERRED RESPONSE 141..: 3- Adenocarcinoma of the breast PREFERRED RESPONSE 142…: 2- Prostate cancer PREFERRED RESPONSE143..: 1- Multiple myeloma