Menu

10. Pathology and Oncology MCQs

Practice Set 75 of 351

This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1481

Topic: 10. Pathology and Oncology

A 21-year-old collegiate female cross-country athlete reports right hip pain that begins about 12 miles into a run, followed by pain resolution when she discontinues running. However, each time she tries to resume a running program, she experiences recurrence of pain deep in the anterior groin. A plain radiograph and MRI scan are shown in Figures 8a and 8b. Management should consist of

. cessation of running and implementation of cross training until healing is complete.
. a bone scan, skeletal survey, and chest radiographs to assess for other sites of involvement.
. a radioisotope injection and scintinigraphic-guided percutaneous biopsy.
. percutaneous fixation with multiple cannulated screws.
. excision, bone grafting, and internal fixation.

Correct Answer & Explanation

. cessation of running and implementation of cross training until healing is complete.

Explanation

DISCUSSION: The history is consistent with a stress fracture.  Findings on the plain radiograph are marginal, but the MRI scan shows evidence of stress reaction in the medial neck of the femur (compression side).  A lesion on the compression side is not normally at risk for displacement and usually can be managed nonsurgically.  A bone scan would further identify the lesion but is not necessary.  A skeletal survey and chest radiograph are used in staging a tumor.  Radioisotope injection and guided biopsy are sometimes used for osteoid osteomas.REFERENCES: Boden BP, Osbahr DC: High-risk stress fractures: Evaluation and treatment.  J Am Acad Orthop Surg 2000;8:344-353.Lynch SA, Renstrom PA: Groin injuries in sport: Treatment strategies.  Sports Med 1999;28:137-144.

Question 1482

Topic: 10. Pathology and Oncology

Serum parathyroid hormone level The plain radiograph of the shoulder shows lytic lesions in the scapular spine, distal clavicle, and the proximal third of the clavicle. There is an elliptical erosion in the proximal clavicle. These three lesions suggest a diagnosis of metastatic bone disease or multiple myeloma. The biopsy specimen shows plasma cells. The plasma cells have these characteristic features: Eccentrically placed nucleus Peripheral clumping of the nuclear chromatin A perinuclear halo The diagnosis is multiple myeloma. Staging is important and is performed with a skeletal survey, bone marrow biopsy, hemoglobin level, and chemistry studies including kidney function and serum calcium determination. Serum protein electrophoresis is performed to assess the amount of abnormal gammaglobulin in the serum. There are three major criteria in the diagnosis of multiple myeloma:

. Plasmacytoma on tissue biopsy
. Bone marrow plasmacytosis greater than 30% plasma cells
. Monoclonal immunoglobulin spike on serum protein electrophoresis exceeding 3.5 g/dl for G peaks or 2.0 g/dl for A peaks or 1.0 g/24 hours of kappa or lamba light chain excretion on urine electrophoresis

Correct Answer & Explanation

. Plasmacytoma on tissue biopsy

Explanation

Slide 1 Slide 2A 55-year old man presents with a 4-month history of shoulder discomfort. The plain radiographs are shown in Slide 1 and a biopsy in Slide 2. Which of the following tests will probably be abnormal:

Question 1483

Topic: 10. Pathology and Oncology

..First-line treatment recommendations include

. synovectomy.
. arthrocentesis, compressive wrap, and rest.
. en bloc resection.
. 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.

Correct Answer & Explanation

. synovectomy.

Explanation

RESPONSES FOR QUESTIONS 47 THROUGH 52UltrasoundMRI scan of the thighChest CT scan and whole-body bone scanPositron emission tomography (PET) scanPresurgical radiation therapyMarginal resectionRadical resection and postsurgical radiationTransverse incision centered over the massIncision centered over the mass in line with long axis of limbSentinel node biopsyCore needle biopsyFor each soft-tissue mass clinical scenario or question below, match the most appropriate next evaluation or treatment step listed above.

Question 1484

Topic: 10. Pathology and Oncology

A 19-year-old girl has had pain and swelling in the right ankle for the past 4 months. She denies any history of trauma. Examination reveals a small soft-tissue mass over the anterior aspect of the ankle and slight pain with range of motion of the ankle joint. The examination is otherwise unremarkable. A radiograph and MRI scan are shown in Figures 45a and 45b, and biopsy specimens are shown in Figures 45c and 45d. What is the most likely diagnosis?

. Osteogenic sarcoma
. Ewing’s sarcoma
. Giant cell tumor of bone
. Aneurysmal bone cyst
. Metastatic adenocarcinoma

Correct Answer & Explanation

. Osteogenic sarcoma

Explanation

DISCUSSION: Giant cell tumors typically occur in a juxta-articular location involving the epiphysis and metaphysis of long bones, usually eccentric in the bone.  The radiographs show a destructive process within the distal tibia and an associated soft-tissue mass.  The histology shows multinucleated giant cells in a bland matrix with a few scattered mitoses.  Osteosarcoma can have a similar destructive appearance but a very different histologic pattern with osteoid production.  Ewing’s sarcoma also can have a diffuse destructive process in the bone.  The histologic pattern of Ewing’s sarcoma is diffuse round blue cells.  Aneurysmal bone cysts typically are seen as a fluid-filled lesion on imaging studies and have only a scant amount of giant cells histologically.  Metastatic adenocarcinoma does not demonstrate the pattern shown in the patient’s histology specimen.REFERENCES: Wold LA, et al: Atlas of Orthopaedic Pathology.  Philadelphia, PA, WB Saunders, 1990, pp 198-199.Simon M, et al: Surgery for Bone and Soft Tissue Tumors.  Philadelphia, PA, Lippincott Raven, 1998, pp 200-202.

Question 1485

Topic: 10. Pathology and Oncology

What is a common clinical finding in patients with severe hypercalcemia secondary to bony metastasis?

. Atrial fibrillation
. Seizures
. Urinary retention
. Muscle weakness
. Hyperreflexia

Correct Answer & Explanation

. Atrial fibrillation

Explanation

DISCUSSION: Increased levels of calcium are known to cause anorexia, nausea, vomiting, dehydration, muscle weakness, polyuria, and polydipsia.  Treatment may include hydration, saline diuresis, and bisphosphonates.REFERENCE: Frassica FJ, Gitelis S, Sim FH: Metastatic bone disease: General principles, pathophysiology, evaluation, and biopsy.  Instr Course Lect 1992;41:293-300.

Question 1486

Topic: 10. Pathology and Oncology

A 34-year-old woman reports constant midlateral arm pain after sustaining minimal trauma to the shoulder. Radiographs and a biopsy specimen are shown in Figures 29a and 29b. What is the most likely diagnosis?

. Chondroblastoma
. Lymphoma
. Giant cell tumor
. Chondromyxoid fibroma
. Desmoplastic fibroma

Correct Answer & Explanation

. Chondroblastoma

Explanation

DISCUSSION: Eighty percent of giant cell tumors occur in patients older than age 20 years, with the peak incidence in the third decade of life.  Most of these tumors are eccentrically located and epiphyseal in location.  They are lytic in nature as in this patient. Although named for the hallmarked multinucleated giant cells seen in the lesion, the basic cell type is the spindle-shaped stromal cell.  Chondroblastoma is highly cellular and contains large multinucleated giant cells with intercellular chondroid material, some of which is calcified.  Chondromyxoid fibroma has chondroid tissue separated by strands of more cellular tissue with occasional multinucleated giant cells.  Desmoplastic fibroma is characterized by poorly cellular fibrous tissue, and lymphoma is highly cellular with characteristic round cells.REFERENCES: Campanacci M, Baldini N, Boriani S, et al: Giant cell tumor of bone.  J Bone Joint Surg Am 1987;69:106-114.Goldenberg RR, Campbell CJ, Bonfiglio M: Giant cell tumor of bone: An analysis of two hundred and eighteen cases.  J Bone Joint Surg Am 1970;52:619-664.

Question 1487

Topic: 10. Pathology and Oncology

Decreased activity of which of the following proteins may be predictive of an aggressive soft-tissue sarcoma?

. Matrix metalloproteinases (MMP)
. Interleukin-1
. Vascular endothelial growth factor
. Tissue inhibitor of metalloproteinases (TIMP)
. Stromelysin

Correct Answer & Explanation

. Matrix metalloproteinases (MMP)

Explanation

DISCUSSION: It has been proposed that an imbalance in the proteolytic cascade involving matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) may play a role in the development or progression of malignancy.  TIMP activity has been shown to be weak or nonexistent and MMP activity to be high in patients with soft-tissue sarcoma.  The level of vascular endothelial growth factor is shown to be a negative prognostic indicator because the expression of this factor is associated with angiogenesis and aggressive growth of many tumors including Ewing’ s sarcoma and chondrosarcoma.  Stromelysin is a type of MMP.  The biology of cytokines in malignancy is complex.  A low level of interleukin-1 is not known to be associated with high-grade tumors.REFERENCE: Benassi MS, Magagnoli G, Ponticelli F, et al: Tissue and serum loss of metalloproteinase inhibitors in high grade soft tissue sarcomas.  Histol Histopathol 2003;18:1035-1040.

Question 1488

Topic: Bone Tumors

Primary chondrosarcoma of bone most commonly occurs in which of the following locations?

. Hand
. Knee
. Shoulder
. Spine
. Pelvis

Correct Answer & Explanation

. Hand

Explanation

DISCUSSION: The most common location of chondrosarcoma is the pelvis (30%), followed by the proximal femur (20%) and shoulder girdle (15%).  Chondrosarcoma rarely affects the spine or hand.REFERENCES: Lee FY, Mankin HJ, Fondren G, et al: Chondrosarcoma of bone: An assessment of outcome.  J Bone Joint Surg Am 1999;81:326-338.Simon M, Springfield D, et al: Chondrosarcoma: Surgery for Bone and Soft Tissue Tumors.  Philadelphia, PA, Lippincott Raven, 1998, p 276.

Question 1489

Topic: 10. Pathology and Oncology

What is the goal of surgical treatment in this scenario?

. To cure cancer
. To prolong life
. To relieve pain
. To reverse neurologic symptoms

Correct Answer & Explanation

. To cure cancer

Explanation

DISCUSSIONThis patient has a metastatic neuroendocrine tumor. Surgical treatment should prioritize palliation of her symptoms. She has high-grade spinal cord compression without neurologic signs or symptoms. Steroids are beneficial for patients with high-grade spinal cord compression caused by tumors, and these drugs should be administered in the acute setting. This patient was appropriately initially treated with conventional radiation. However, she is not a candidate for further radiation because of spinal cord tolerance limits and insufficient clearance between the tumor and spinal cord. Consequently, stereotactic radiation is not an option.The goal of surgical treatment of this tumor should be palliation of her symptoms rather than cure. A costotransversectomy approach offers the advantage of ventral and dorsal spinal cord access, which is necessary in this case. A sternotomy or transthoracic approach would offer ventral access, but dorsal access would be less than optimal.RECOMMENDED READINGSRose PS, Buchowski JM. Metastatic disease in the thoracic and lumbar spine: evaluation and management. J Am Acad Orthop Surg. 2011 Jan;19(1):37-48. Review. PubMed PMID: 21205766.View Abstract at PubMedRades D, Abrahm JL. The role of radiotherapy for metastatic epidural spinal cord compression. Nat Rev Clin Oncol. 2010 Oct;7(10):590-8. doi: 10.1038/nrclinonc.2010.137. Epub 2010 Aug

Question 1490

Topic: 10. Pathology and Oncology

Eosinophilic granuloma frequently occurs as a solitary lesion in the tubular long bones. After biopsy, what is the best course of action?

. Neoadjuvant chemotherapy
. En bloc resection
. Observation
. Amputation
. Chemotherapy followed by radiation therapy

Correct Answer & Explanation

. Neoadjuvant chemotherapy

Explanation

DISCUSSION: Most lesions of eosinophilic granuloma are simply observed, but larger aggressive lesions may require curettage and bone grafting.  Frequently, biopsy is required to rule out a malignant diagnosis.  The differential diagnosis of eosinophilic granuloma is osteomyelitis, Ewing’s sarcoma of bone, or osteogenic sarcoma.  The biopsy alone can be followed by spontaneous resolution.  In some patients, low-dose radiation therapy is used.  Chemotherapy or amputation is not indicated for these benign lesions.REFERENCE: Simon M, Springfield D, et al: Common Benign Bone Tumors: Surgery for Bone and Soft Tissue Tumors.  Philadelphia, PA, Lippincott Raven, 1998, p 200.

Question 1491

Topic: 10. Pathology and Oncology

Acral metastases are most commonly seen in what type of carcinoma?

. Renal cell
. Lung
. Thyroid
. Breast
. Ovarian

Correct Answer & Explanation

. Renal cell

Explanation

DISCUSSION: Metastatic lesions to bone are usually located in the axial and proximal appendicular skeleton.  Metastases below the elbow and knee are rare, but when they do occur they are most commonly from lung carcinoma.REFERENCES: Hayden RJ, Sullivan LG, Jebson PJ: The hand in metastatic disease and acral manifestations of paraneoplastic syndromes.  Hand Clin 2004;20:335-343.Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors.  Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, p 313.

Question 1492

Topic: 10. Pathology and Oncology

A 7-year-old boy has a limp with pain and tenderness over the distal right femur. Radiographs are shown in Figures 5a and 5b. Based on these findings, what is the best course of action?

. Observation
. Radiofrequency ablation
. Biopsy, curettage, and bone grafting
. Radiation therapy
. Steroid injection

Correct Answer & Explanation

. Observation

Explanation

DISCUSSION: The patient has a nonossifying fibroma, and the symptoms suggest that there is significant weakening of the cortex and/or microfracture; therefore, biopsy, curettage, and bone grafting is the treatment of choice.  Based on the size of the lesion and the presence of symptoms, observation is likely to result in pathologic fracture.  A biopsy will further weaken the bone unless combined with curettage and bone grafting.  Radiation therapy is not used in the treatment of nonossifying fibroma and is rarely used in any benign condition affecting skeletally immature individuals.  Steroid injection has been used in the treatment of unicameral bone cysts and in Langerhan’s cell histiocytosis but not for nonossifying fibroma.REFERENCES: Dormans, JP, Pill SG: Fractures through bone cysts: Unicameral bone cysts, aneurysmal bone cysts, fibrous cortical defects, and nonossifying fibromas.  Instr Course Lect 2002;51:457-467.Easley ME, Kneisl JS: Pathologic fractures through nonossifying fibromas: Is prophylactic treatment warranted?  J Pediatr Orthop 1997;17:808-813.

Question 1493

Topic: 10. Pathology and Oncology

A 7-year-old girl has pain and a mass in the left scapula. A MRI scan and biopsy specimen are shown in Figures 30a and 30b. After staging studies, initial management should consist of

. radiation therapy to the scapula.
. systemic chemotherapy.
. total scapulectomy.
. partial scapulectomy.
. intravenous antibiotics.

Correct Answer & Explanation

. radiation therapy to the scapula.

Explanation

DISCUSSION: The histology shows small round blue cells that are uniform in appearance; these findings are consistent with Ewing’s sarcoma.  The MRI scan shows infiltration of the marrow and a large surrounding soft-tissue mass.  Based on these findings, the management of choice is systemic chemotherapy.  Local control of the primary lesion is addressed by either surgical resection or radiation therapy or a combination of the two after the patient receives systemic chemotherapy.  The clinical, radiographic, and histologic presentation of Ewing’s sarcoma often can be confused with osteomyelitis.  The histology shows an absence of inflammatory cells.REFERENCES: Grier HE: The Ewing family of tumors: Ewing’s sarcoma and primitive neuroectodermal tumors.  Pediatr Clin North Am 1997;44:991-1004.Arndt CA, Crist WM: Common musculoskeletal tumors of childhood and adolescence.  N Engl J Med 1999;341:342-352.

Question 1494

Topic: Bone Tumors

A 17-year-old girl who initially presented as a child with multiple skeletal lesions, café-au-lait spots, and precocious puberty now has bone pain. A recent bone scan reveals multiple areas of increased scintigraphic uptake, including bilateral proximal femurs. A radiograph is shown in Figure 19. Besides activity modification, what is the next best line of treatment for decreasing her pain? Review Topic

. Bisphosphonates
. Calcitonin
. Parathyroid hormone
. Vitamin D and calcium
. Methotrexate

Correct Answer & Explanation

. Bisphosphonates

Explanation

McCune-Albright syndrome is the combination of polyostotic fibrous dysplasia, café-au-lait lesions, and endocrine dysfunction. The most common endocrine presentation is precocious development of secondary sexual characteristics. Compared with bone lesions in patients without polyostotic disease, the skeletal lesions in patients with the syndrome tend to be larger, more persistent, and associated with more complications. Bisphosphonate therapy has been shown in several studies to decrease the pain associated with the skeletal lesions of fibrous dysplasia.

Question 1495

Topic: 10. Pathology and Oncology

A 37-year-old man pulled his hamstring playing softball 3 weeks ago. The patient had not noted any mass prior to his injury. MRI scans of the posterior thigh are shown in Figures 4a and 4b. Figure 4c shows the biopsy specimen from a needle biopsy. What is the most likely diagnosis?

. Intramuscular hematoma
. Lipoma
. Myositis ossificans
. Malignant fibrous histiocytoma
. Liposarcoma

Correct Answer & Explanation

. Intramuscular hematoma

Explanation

DISCUSSION: Malignant fibrous histiocytoma (MFH) is the most common soft-tissue sarcoma.  MFH typically presents as a large mass, deep to the fascia with heterogeneous signal on MRI.  The MRI scans show a heterogeneous lesion in the posterior thigh.  There is significant high signal uptake on the T2-weighted image.  The histology shows malignant histiocytic cells with marked atypia and pleomorphism.  Histology of a hematoma would show only old hemorrhage and some granulation tissue.  Lipoma and liposarcoma are both seen as a fat-containing lesion on histology.  No significant fat tissue is seen in this histologic specimen.  Histology of myositis ossificans would show bone formation.REFERENCES: Simon SR (ed): Orthopaedic Basic Science.  Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 219-276.Campanacci M: Bone and Soft Tissue Tumors, ed 2.New York, NY, Springer-Verlag, 1999, pp 965-981.

Question 1496

Topic: 10. Pathology and Oncology

A morbidly obese 80-year-old woman presents with back pain for 2 months. Sagittal T2-weighted, sagittal T1-weighted, coronal short tau inversion recovery (STIR) images are shown in Figures A through C, respectively. Which of the following statements is true of her diagnosis? Review Topic

. MR fluid sign suggests that this is an osteoporotic vertebral compression fracture
. Convex posterior vertebral border suggests that this is an osteoporotic vertebral compression fracture
. Replacement of the normal marrow signal suggests that this is a malignant vertebral compression fracture
. Retropulsion of a vertebral body fragment suggests that this is a malignant vertebral compression fracture
. The band-like low T1 signal suggests that this is a malignant vertebral compression fracture

Correct Answer & Explanation

. MR fluid sign suggests that this is an osteoporotic vertebral compression fracture

Explanation

The MR fluid sign is highly suggestive of an osteoporotic vertebral compression fracture (VCF).The MR signs suggestive of a benign, osteoporotic VCF include band-like low T1 signal, fluid sign, retropulsion of a vertebral bone fragment. Acute fractures show low signal on T1-weighted and high signal on T2-weighted and STIR images. The MR signs suggestive of malignant VCF include complete replacement of normal marrow signal, convex posterior vertebral border, pedicle involvement, focal paraspinal mass and epidural mass.Kim et al. performed a literature review on management of the osteoporotic spine. They concluded that nonsurgical management should focus on pain control and maximizing function. Surgery remains controversial and should be reserved for those who fail nonoperative management. Surgical options include vertebroplasty, balloon tamp reduction, and decompression and instrumented fusion with structural graft and multiple fixation points.Spivak et al. discussed percutaneous treatment of VCF. They recommend vertebroplasty for patients with unremitting pain and little deformity as it is less costly and does not require general anesthesia. They recommend kyphoplasty for cases withgreater vertebral collapse, especially subacute fractures where partial healing may hinder postural fracture reduction.Figure A is a T2-weighted sagittal MR image showing a fluid-filled cleft ("fluid sign"). Figure B is a T1-weighted sagittal MR image showing loss of intensity (black) consistent with vertebral body edema. Figure C is a coronal STIR image showing the fluid-filled vertebral body cleft. An incidental renal cyst is noted. Illustration A shows different patterns of band-like signal abnormality on T1-weighted imaging. The black region represents low signal intensity (edema). Illustration B is a sagittal STIR image showing the MR fluid sign. Illustration C shows the band like signal abnormality on T1-weighted imaging. Illustration D shows metastatic disease with complete replacement of normal marrow intensity and diffuse convexity of the posterior vertebral border.Incorrect

Question 1497

Topic: Bone Tumors

A 40-year-old man with an acetabular chondrosarcoma has a small soft-tissue mass. Treatment should consist of

. chemotherapy with ifosfamide and doxorubicin hydrochloride.
. external beam radiation.
. wide resection.
. curettage and cementation of the pelvic lesion.
. cemented total hip arthroplasty with acetabular reconstruction.

Correct Answer & Explanation

. chemotherapy with ifosfamide and doxorubicin hydrochloride.

Explanation

DISCUSSION: The treatment of choice for pelvic chondrosarcoma is wide resection via an internal hemipelvectomy.  Chondrosarcoma requires surgical resection for control and does not respond to traditional chemotherapy or external beam radiation.  Hip arthroplasty with acetabular reconstruction and curettage and cementation of the lesion are intralesional procedures that result in a higher incidence of local recurrence of tumor.REFERENCES: Pring M, Weber KL, Unni K, Sim FH: Chondrosarcoma of the pelvis: A review of sixty-four cases.  J Bone Joint Surg Am 2001;83:1630-1642.Sheth DS, Yasko AW, Johnson ME, Ayala AG, Murray JA, Romsdahl MM: Chondrosarcoma of the pelvis: Prognostic factors for 67 patients treated with definitive surgery.  Cancer 1996;78:745-750.

Question 1498

Topic: Bone Tumors

Nonossifying fibroma

. Cortical thickening in the region of the lesion
. Erosive metaphyseal lesion with loss of cortical integrity
. Normal bony anatomy on radiographs
. Diffuse articular erosion with loss of joint space
. Round, expansive, well-circumscribed metaphyseal lesion with thinning of the cortex
. Eccentric well-circumscribed metaphyseal lesion with a scalloped border

Correct Answer & Explanation

. Cortical thickening in the region of the lesion

Explanation

DISCUSSIONEarly osteomyelitis and septic arthritis appear as normal bony anatomy on radiographs, with perhaps only soft-tissue swelling seen. Radiographic changes with metaphyseal erosion appear in a delayed fashion, often after 7 or more days in indolent infections, but may present earlier in association with virulent infections such as methicillin-resistant Staphylococcus aureus. Osteoid osteoma has a radiolucent small nidus that may be difficult to see on radiograph; however, chronic cases cause marked cortical hypertrophy. Unicameral bone cysts are expansile metaphyseal lesions that are never wider than the physis. They are symmetric, well circumscribed, and can have cortical thinning. When fractures through the cyst arepresent, the fallen leaf sign is visible as cortical fragments fall to the bottom of the cyst. Nonossifying fibromas are eccentric metaphyseal lesions with scalloped borders.

Question 1499

Topic: Bone Tumors

A 62-year-old woman reports diffuse aches and pains of the hip and pelvis. She denies any significant trauma but does have a history of chronic anemia. Figure 17a shows a radiograph of the pelvis, and Figures 17b and 17c show T 2 -weighted MRI scans. What is the most likely diagnosis?

. Chondrosarcoma
. Diffuse fibrous dysplasia
. Multiple myeloma
. Osteoporosis
. Bone infarcts

Correct Answer & Explanation

. Chondrosarcoma

Explanation

DISCUSSION: The radiograph reveals diffuse osteopenia and areas in the proximal femora that are moth-eaten in appearance.  The extent of the marrow-replacing process is evident on the MRI scans, which reveal signal abnormality throughout the entire pelvis and both proximal femora.  This represents a marrow-packing process, of which multiple myeloma is the best choice.  This diagnosis is also supported by the anemia noted on the patient’s history.  Metastatic carcinoma and lymphoma also may have a similar presentation.REFERENCE: Resnick D (ed): Diagnosis of Bone and Joint Disorders.  Philadelphia, PA,WB Saunders, 2002, pp 2189-2216.

Question 1500

Topic: 10. Pathology and Oncology

Figures 61a and 61b show the CT and MRI scans of a 40-year-old man who has hip pain. He undergoes total hip arthroplasty and curettage and cementation of the lesion as shown in Figure 61c. Histopathologic photomicrographs of the curettage specimen are shown in Figures 61d and 61e. What is the best course of treatment?

. Observation
. Revision and removal of any remaining gross disease
. Hemipelvectomy
. Exploration and repeat curettage
. Hip disarticulation

Correct Answer & Explanation

. Hemipelvectomy

Explanation

DISCUSSION: The definitive surgery would be removal of the entire resection bed, and in this case of dedifferentiated chondrosarcoma, a hemipelvectomy was performed.  The MRI and CT scans show an aggressive cartilage lesion.  The histology, representative of a dedifferentiated chondrosarcoma, shows a bimorphic low-grade cartilage lesion with high-grade spindle cell sarcoma.  The cartilage lesion is usually an enchondroma or low-grade chondrosarcoma.  The dedifferentiated portion is typically a malignant fibrous histocytoma, osteosarcoma, or fibrosarcoma.REFERENCES: Weber KL, Pring ME, Sim FH: Treatment and outcome of recurrent pelvic chondrosarcoma. Clin Orthop Relat Res 2002;397:19-28.Pring ME, Weber KL, Unni KK, et al: Chondrosarcoma of the pelvis: A review of sixty-four cases.  J Bone Joint Surg Am 2001;83:1630-1642

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page