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10. Pathology and Oncology MCQs

Practice Set 98 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 1941

Topic: Bone Tumors

A 17-year-old male presents with night pain in the proximal femur that is dramatically relieved by NSAIDs. CT scan shows a 7 mm radiolucent nidus surrounded by dense sclerotic bone in the femoral neck, located 3 mm from the articular cartilage. What is the most appropriate definitive management?

. Percutaneous radiofrequency ablation
. Observation alone
. Intralesional curettage or en bloc excision
. Intravenous bisphosphonates
. Radiation therapy

Correct Answer & Explanation

. Intralesional curettage or en bloc excision

Explanation

The diagnosis is osteoid osteoma. While radiofrequency ablation (RFA) is the standard of care for most osteoid osteomas, lesions located within 1-1.5 cm of critical structures such as articular cartilage or major nerves are generally considered contraindicated for RFA due to the high risk of thermal necrosis to the cartilage. In this case, surgical curettage or excision is the preferred treatment.

Question 1942

Topic: 10. Pathology and Oncology

A 60-year-old female with breast cancer presents with moderate thigh pain. Radiographs reveal a lytic lesion in the peritrochanteric region of the proximal femur that occupies less than 1/3 of the cortical diameter. What is her Mirels' score and the corresponding recommendation?

. Score 7: Radiation therapy only
. Score 8: Clinical judgment / borderline
. Score 9: Prophylactic fixation indicated
. Score 10: Prophylactic fixation indicated
. Score 11: Immediate non-weight bearing only

Correct Answer & Explanation

. Score 9: Prophylactic fixation indicated

Explanation

Mirels' criteria for impending pathologic fracture: Site (Peritrochanteric = 3), Pain (Moderate = 2), Lesion (Lytic = 3), Size (<1/3 = 1). Total score = 3+2+3+1 = 9. A score of 9 or greater carries a high risk of fracture (>=33%), and prophylactic surgical fixation is strictly recommended.

Question 1943

Topic: 10. Pathology and Oncology

A 55-year-old male presents with chronic sacral pain and bowel dysfunction. Imaging reveals a large, destructive, midline mass in the sacrum. Histological examination shows physaliferous cells with vacuolated cytoplasm in a myxoid background. The tumor is positive for brachyury. What is the most important factor in determining the patient's overall survival?

. Tumor response to systemic chemotherapy
. Tumor response to conventional external beam radiation
. Obtaining wide surgical margins during resection
. The specific somatic mutation in the brachyury gene
. The presence of skip lesions on initial MRI

Correct Answer & Explanation

. Obtaining wide surgical margins during resection

Explanation

The diagnosis is a sacral chordoma, which is positive for the transcription factor brachyury. Chordomas are locally aggressive malignant tumors notoriously resistant to conventional chemotherapy and radiation. The single most important factor determining local recurrence and overall survival is obtaining wide, en bloc surgical margins during the initial resection.

Question 1944

Topic: 10. Pathology and Oncology

A 14-year-old male is diagnosed with Ewing sarcoma of the femoral diaphysis. He undergoes neoadjuvant chemotherapy, followed by wide surgical excision. Pathology of the resected specimen reveals 95% tumor necrosis. Which of the following statements best describes the significance of this finding?

. It indicates a high risk of local recurrence and warrants immediate amputation
. It is an expected finding but has no significant bearing on overall prognosis
. It is a highly favorable prognostic indicator correlated with improved disease-free survival
. It mandates a change in the postoperative chemotherapy regimen to salvage agents
. It suggests the original diagnosis was likely a malignant lymphoma rather than Ewing sarcoma

Correct Answer & Explanation

. It is a highly favorable prognostic indicator correlated with improved disease-free survival

Explanation

In Ewing sarcoma (and osteosarcoma), the degree of tumor necrosis following neoadjuvant chemotherapy is one of the most powerful independent prognostic indicators. A good histologic response (defined as >=90% or >=95% tumor necrosis) is strongly correlated with improved local control, disease-free survival, and overall survival.

Question 1945

Topic: 10. Pathology and Oncology

A 30-year-old female presents with chronic recurrent bloody knee effusions without any history of trauma. MRI of the knee demonstrates a nodular intra-articular mass with low signal intensity on both T1 and T2 sequences, accompanied by a 'blooming' artifact on gradient-echo sequences. What is the most likely diagnosis?

. Synovial chondromatosis
. Hemangioma
. Tenosynovial giant cell tumor
. Synovial sarcoma
. Lipoma arborescens

Correct Answer & Explanation

. Tenosynovial giant cell tumor

Explanation

Tenosynovial giant cell tumor (formerly known as Pigmented Villonodular Synovitis or PVNS) classically presents with recurrent hemarthrosis. The MRI pathognomonic finding is low T1/T2 signal with 'blooming' artifact due to hemosiderin deposition within the tumor.

Question 1946

Topic: 10. Pathology and Oncology
A 14-year-old boy is diagnosed with osteoblastic osteosarcoma of the distal femur. Following neoadjuvant chemotherapy, he undergoes wide surgical resection. According to the Huvos grading system, what percentage of tumor necrosis defines a 'good responder' and indicates a better long-term prognosis?
. Greater than 50%
. Greater than 75%
. Greater than 90%
. Greater than 95%
. 100% only

Correct Answer & Explanation

. Greater than 90%

Explanation

The Huvos grading system categorizes the histologic response of osteosarcoma to chemotherapy. A 'good response' (Grade III or IV) is defined as having greater than 90% tumor necrosis, which is a major prognostic indicator for improved survival.

Question 1947

Topic: 10. Pathology and Oncology

A 55-year-old male presents with an incidental 6 cm intraosseous lesion in the proximal tibia. Radiographs show classic ring-and-arc calcifications. A biopsy demonstrates a low-grade (Grade 1) central chondrosarcoma confined strictly to the medullary canal without cortical breakthrough. What is the standard surgical management?

. Wide en bloc resection and endoprosthetic reconstruction
. Extended intralesional curettage with local adjuvants followed by bone grafting or cementation
. Preoperative radiation therapy followed by wide resection
. Neoadjuvant chemotherapy followed by wide resection
. Above-knee amputation

Correct Answer & Explanation

. Extended intralesional curettage with local adjuvants followed by bone grafting or cementation

Explanation

Low-grade (Grade 1) central chondrosarcomas, also termed atypical cartilaginous tumors, that are confined to the medullary canal can be safely managed with extended intralesional curettage, high-speed burring, and local adjuvants. This avoids the morbidity of wide resection while maintaining excellent local control.

Question 1948

Topic: 10. Pathology and Oncology
An 11-year-old girl has wrist pain. Figure 4a shows the radiograph, and Figures 4b and 4c show the low- and medium-power photomicrographs of a lesion in the distal radius. What is the most likely diagnosis?
. Simple bone cyst
. Nonossifying fibroma
. Osteomyelitis
. Aneurysmal bone cyst
. Giant cell tumor

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

The radiograph shows an osteolytic eccentric lesion in the metaphyseal-diaphyseal region of the bone, and the photomicrographs show an aneurysmal bone cyst. The low-power photomicrograph shows large empty spaces with fibrous stroma and multinucleated giant cells. The red area in the center is hemorrhage in the stroma. The large empty spaces are cysts, which would be filled with blood in vivo. The medium-power photomicrograph shows a large cyst-like space and hemorrhage in the surrounding stroma. Giant cell tumors have โ€œsheetsโ€ of giant cells. A nonossifying fibroma would have spindle cells, and a unicameral bone cyst may have a few giant cells, but blood is rare.

Question 1949

Topic: 10. Pathology and Oncology
A 21-year-old man is referred for evaluation of a lesion in the left proximal femur that was discovered when he was undergoing an upper gastrointestinal series. He reports no hip or thigh pain. Radiographs are shown in Figures 64a and 64b. What is the best course of action?
. Observation
. Needle biopsy
. Incisional biopsy
. Curettage
. Wide resection

Correct Answer & Explanation

. Observation

Explanation

Melorheostosis is a rare disorder characterized by the classic radiographic appearance of flowing hyperostosis in a long bone. The hyperostosis may be on the periosteal or endosteal surface of the bone and frequently gives the appearance of wax falling down the side of a candle. The radiographs are diagnostic; therefore, no further work-up is indicated.

Question 1950

Topic: 10. Pathology and Oncology

..Figures 3a and 3b are the radiographs of a 5-year-old child with midtibia swelling and no pain. What isthe most appropriate next step?

. Bone scan
. Observation
. Needle biopsy
. Wide excision
. Referral to a musculoskeletal tumor service for definitive treatment

Correct Answer & Explanation

. Bone scan

Explanation

Question 1951

Topic: Bone Tumors
Compared with amputation, limb salvage for osteosarcoma of the distal end of the femur will result in:
. an improved chance for long-term survival.
. an improved quality of life.
. a lessened need for chemotherapy.
. a better functional outcome.
. a reduced need for reoperation.

Correct Answer & Explanation

. a better functional outcome.

Explanation

Major advances in diagnostic imaging, neoadjuvant chemotherapy, and surgical techniques have allowed limb salvage to be performed as an alternative to amputation in children with osteosarcoma. The outcome of treatment of nonmetastatic, high-grade osteosarcoma of the distal femur was studied in 227 patients from 26 institutions. The authors found no difference in the long-term survival or quality of life between patients treated with limb salvage and those treated with amputation. Patients treated with limb salvage had a higher rate of reoperation, but a better functional outcome.

Question 1952

Topic: 10. Pathology and Oncology

A 60-year-old male presents with worsening sacral pain and bowel/bladder dysfunction. Imaging reveals a large, destructive, midline lytic lesion involving the S2-S4 segments. Biopsy demonstrates a lobulated architecture with physaliferous cells containing large intracytoplasmic vacuoles. What is the recommended treatment?

. Neoadjuvant chemotherapy followed by curettage
. Wide en bloc surgical resection
. Definitive radiation therapy alone
. Intralesional excision with phenol adjuvant
. Radiofrequency ablation

Correct Answer & Explanation

. Wide en bloc surgical resection

Explanation

The biopsy findings of physaliferous cells in a midline sacral mass are pathognomonic for chordoma. Chordomas are locally aggressive and largely resistant to standard chemotherapy and radiation, making wide en bloc surgical excision the definitive treatment of choice.

Question 1953

Topic: 10. Pathology and Oncology
What is the most significant factor affecting long-term survival for a patient with bone sarcoma?
. Presence of metastatic disease at presentation
. Grade of tumor
. Size of tumor
. Depth of tumor invasion
. Presence of necrosis

Correct Answer & Explanation

. Presence of metastatic disease at presentation

Explanation

The most significant impact on long-term survival is the presence or absence of identifiable metastatic disease on initial presentation. All of these factors have been shown to be predictive of long-term survival to varying degrees.

Question 1954

Topic: 10. Pathology and Oncology
A 35-year-old patient has right hip pain. Figures 34a and 34b show the coronal MRI scan and the biopsy specimen. What is the most likely diagnosis?
. Degenerative cyst with collapse
. Osteonecrosis
. Chondroblastoma
. Metastatic carcinoma
. Clear cell chondrosarcoma

Correct Answer & Explanation

. Osteonecrosis

Explanation

DISCUSSION: Alcohol abuse, steroids, Caisson disease, sickle cell disease, and radiation therapy are the leading causes of nontraumatic osteonecrosis of the femoral head. REFERENCES: Arlet J: Nontraumatic avascular necrosis of the femoral head: Past, present, and future. Clin Orthop 1992;277:12-21. Stulberg BN, Bauer TW, Belhobek GH, Levine M, Davis A: A diagnostic algorithm for osteonecrosis of the femoral head. Clin Orthop 1989;249:176-182.

Question 1955

Topic: Bone Tumors
Figures 4a through 4c show the radiographs, CT scans, and T1-weighted MRI scan of a 19-year-old man who has had increasing right hip pain and decreasing range of motion for the past several years. He also reports intermittent โ€œlockingโ€ of the hip. What is the most likely diagnosis?
. Chondrosarcoma
. Stress fracture
. Osteochondroma
. Osteosarcoma
. Synovial osteochondromatosis

Correct Answer & Explanation

. Synovial osteochondromatosis

Explanation

DISCUSSION: The radiographs reveal small ossified masses around the femoral neck. The CT scans also show these masses and suggest that they are separate from the underlying cortex of the femoral neck, although they abut it. The MRI scan does not reveal significant marrow changes in the proximal femur apart from some mild reactive changes immediately adjacent to the nodules. These findings suggest a synovial or joint-based disorder as opposed to a primary bone tumor. The most likely diagnosis is synovial osteochondromatosis, which is consistent with the patientโ€™s mechanical symptoms. REFERENCES: Crotty JM, Monu JU, Pope TL Jr: Synovial osteochondromatosis. Radiol Clin North Am 1996;34:327-342. Frassica F: Orthopaedic pathology, in Miller M (ed): Review of Orthopaedics, ed 2. Philadelphia, PA, WB Saunders, 1996, pp 292-335.

Question 1956

Topic: 10. Pathology and Oncology

A characteristic genetic translocation has been noted in which of the following tumors?

Basic Science 2002 Practice Questions: Set 1 (Solved) - Figure 16

. Ewing's sarcoma
. Chondrosarcoma
. Neurofibrosarcoma
. Osteosarcoma
. Epithelioid sarcoma

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

There have been no characteristic gene translocations or rearrangements noted in osteosarcoma, chondrosarcoma, neurofibrosarcoma, or epithelioid sarcoma. In contrast, Ewing's sarcoma has been noted to have a consistent genetic translocation t(11:22). Brockstein BE, Peabody TD, Simon MA: Soft tissue sarcomas, in Vokes EE Golomb HM (eds): Oncologic Therapies. New York, NY, Springer-Verlag, 1999, pp 925-952.

Question 1957

Topic: 10. Pathology and Oncology

A 40-year-old man has a painless mass around his left ankle. He notes minimal growth over the past year. An MRI scan is shown in Figure 73a, and biopsy specimens are shown in Figures 73b and 73c. What is the most likely diagnosis?

. Epithelioid sarcoma
. Clear cell sarcoma
. Pigmented villonodular synovitis
. Malignant fibrous histiocytoma
. Synovial sarcoma

Correct Answer & Explanation

. Synovial sarcoma

Explanation

The biopsy specimen is a low-power view of a soft-tissue sarcoma with a biphasic pattern of epithelial cells and fibrous spindle cells that are typical of a synovial sarcoma. A deep, painless soft-tissue mass greater than 5 cm in size is suspicious for a sarcoma. The imaging in this patient is indeterminate and the patient requires a biopsy for an accurate diagnosis. The biopsy reveals a tumor with a biphasic appearance consistent with a synovial sarcoma. These tumors are slow growing, occur primarily in the lower extremities, and are found in a younger demographic population compared to malignant fibrous histiocytoma and liposarcoma. They can occur in a biphasic pattern with clumps of epithelial cells and fibrous spindle cells or in a monophasic pattern. Synovial sarcomas stain positively for keratin. Keratin is positive in nearly all biphasic types and in many tumors of the monophasic fibrous type. Sixty percent of these tumors are found in the lower extremity. The area around the knee is the most common location, followed by the ankle and foot. Epithelioid and clear cell sarcomas are found associated with tendon sheaths of the hand and feet and are generally smaller in size. Epithelioid sarcoma may resemble granulomatous inflammation histologically; clear cell sarcoma is composed of nests of clear cells with occasional multinucleated giant cells. Pigmented villonodular synovitis is found within the synovium and is characterized by a villous histologic appearance with hemosiderin-laden macrophages. Malignant fibrous histiocytoma has a storiform histologic pattern with an abundance of pleomorphic cells. Enzinger FM, Weiss SW: Soft Tissue Tumors, ed 3. St Louis, MO, Mosby, 1995, p 757.

Question 1958

Topic: 10. Pathology and Oncology

A 73-year-old man stepped off a street curb and felt a crack in his left hip. He is now unable to bear weight. A radiograph is shown in Figure 54a. Biopsy specimens are shown in Figures 54b and 54c. What is the most likely diagnosis?

. Synovial sarcoma
. Adamantinoma - metastatic prostate cancer
. Chondrosarcoma
. Dedifferentiated chondrosarcoma
. Periosteal osteosarcoma

Correct Answer & Explanation

. Dedifferentiated chondrosarcoma

Explanation

The biopsy specimens reveal a high-grade spindle cell lesion adjacent to an area of benign cartilage. This is consistent with a dedifferentiated chondrosarcoma. The radiograph shows a pathologic fracture through a lesion characterized by calcification within the left greater trochanter. Distal to the area of calcification, there is a more osteolytic, destructive appearance. Synovial sarcoma has a biphasic appearance histologically with areas of glandular differentiation that stain positive with keratin. Metastatic prostate cancer, although osteoblastic in appearance, would have a glandular histologic appearance. There is no cartilage in these lesions. Classic low-grade chondrosarcoma does not have an area of high-grade pleomorphic spindle cells within the lesion. A periosteal osteosarcoma is a surface-based lesion with a sunburst radiographic pattern. Although there may be cartilage in the lesion histologically, there are also malignant cells producing osteoid. Dedifferentiated chondrosarcoma is an aggressive, high-grade variant of chondrosarcoma. Wold LE, Adler CP, Sim FH, et al: Atlas of Orthopedic Pathology, ed 2. Philadelphia, PA, WB Saunders, 2003, p 269.

Question 1959

Topic: 10. Pathology and Oncology
A 21-year-old man has had progressive right knee pain for the past 2 months that is exacerbated with weight-bearing activities. A plain radiograph and an MRI scan are shown in Figures 43a and 43b. A biopsy specimen is shown in Figure 43c. According to the Enneking staging system of tumor classification, the lesion should be classified as what stage?
. 1
. 2
. 3
. I
. II

Correct Answer & Explanation

. 3

Explanation

The lesion is an eccentric lytic bone lesion within the epiphyseal-metaphyseal end of the proximal tibia. There is geographic destruction with a "fading border" extending to the articular cartilage. There is no matrix formation or periosteal reaction. The MRI scan shows cortical destruction with extension into the soft tissue. According to the Enneking staging system, benign lesions are stage 1, 2, or 3; malignant lesions are stage I, II, or III. Benign stage 1 lesions are latent; stage 2 are active; and stage 3 are benign aggressive. The histology shows a benign giant cell tumor. Given the cortical breakthrough shown on the MRI scan, the lesion should be classified as stage 3. Enneking WF: Clinical musculoskeletal pathology, in Enneking WF (ed): Appendix A. Gainesville, FL, Storter Publishing, 1986, pp 451-466.

Question 1960

Topic: 10. Pathology and Oncology

A 24-year-old man has had pain in the left knee for the past several months. He reports that initially the pain was associated with weight-bearing activities, but it has now become more constant. He denies any swelling but reports a lateral fullness at the tibial plateau. Figures 23a through 23e show radiographs, a bone scan, and T1- and T2-weighted MRI scans. What is the most likely diagnosis?

. Stress fracture
. Simple bone cyst
. Fibrous dysplasia
. Infection
. Giant cell tumor

Correct Answer & Explanation

. Giant cell tumor

Explanation

The radiographs reveal a lytic subchondral lesion that has a poorly defined margin and lacks mineralization. The bone scan confirms an active lesion that has central photopenia, producing the characteristic doughnut configuration. The MRI scans confirm the presence of a subchondral lesion that is modestly expansile at the lateral plateau and has low signal intensity on the T1-weighted image and a mixed high signal on the T2-weighted image. These features strongly suggest giant cell tumor of bone, more than 50% of which appear around the knee. Simple cyst is excluded by the MRI characteristics. Fibrous dysplasia is unlikely to be in a subchondral location and typically does not show this intensity of uptake on bone scan. Parsons TW: Benign bone tumors, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1027-1035.

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