10. Pathology and Oncology MCQs

A 45-year-old man presents with chronic, dull lower back and perineal pain. Advanced imaging reveals a destructive, midline expansile lytic lesion in the sacrum. Histological examination of a biopsy specimen demonstrates large, vacuolated cells with a bubbly cytoplasm arranged in cords within a myxoid background. Which of the following immunohistochemical markers is most likely to be positive in this lesion?

A 16-year-old boy is evaluated for persistent left thigh pain and swelling. Radiographs show a permeative, aggressive diaphyseal lesion in the femur with a prominent 'onion-skin' periosteal reaction. A core needle biopsy is performed. Molecular cytogenetic testing of the biopsy specimen is most likely to reveal which of the following chromosomal translocations?

A 28-year-old man presents with a slow-growing, painless mass in his foot. MRI shows a well-circumscribed soft tissue mass adjacent to the plantar fascia. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. What is the most characteristic chromosomal translocation associated with this diagnosis?

A 12-year-old boy presents with thigh pain and low-grade fevers. Radiographs show a permeative diaphyseal lesion in the femur with a classic 'onion-skin' periosteal reaction. Biopsy shows small round blue cells. Immunohistochemistry is strongly positive for CD99. Which of the following gene fusions is most commonly responsible for this tumor?

A 16-year-old girl is diagnosed with high-grade conventional osteosarcoma of the proximal tibia. She undergoes neoadjuvant chemotherapy followed by wide surgical resection. Which of the following factors has been shown to be the most important prognostic indicator for overall survival in this patient?

A 9-year-old girl presents with a limp. Radiographs of her proximal femur show a characteristic 'shepherd's crook' deformity with a ground-glass appearance of the medullary canal. She also has irregular café-au-lait spots on her trunk and a history of precocious puberty. This condition is primarily caused by a mutation leading to which of the following cellular abnormalities?

A 55-year-old man presents with progressive deep thigh pain, worse at night. Radiographs demonstrate a large, predominantly lytic lesion in the proximal femur with endosteal scalloping greater than two-thirds of the cortical thickness and focal cortical breakthrough. MRI shows a lobulated mass with high signal intensity on T2-weighted images. Biopsy is read as a grade 2 chondrosarcoma. What is the most appropriate definitive management for this patient?

A 14-year-old boy presents with rapid swelling and pain in his left humerus. Radiographs show an expansile, eccentrically located, lytic metaphyseal lesion with 'blown-out' cortices. MRI reveals multiple fluid-fluid levels. Biopsy confirms a primary aneurysmal bone cyst. Primary aneurysmal bone cysts are frequently associated with a recurrent chromosomal translocation resulting in the upregulation of which of the following genes?

A 35-year-old woman presents with chronic, progressive swelling and catching of her right knee. Aspiration yields dark, bloody synovial fluid. MRI reveals a large, lobulated intra-articular mass with 'blooming artifact' on gradient-echo sequences. The pathogenesis of this condition is primarily driven by a translocation resulting in the overexpression of which of the following factors?

A 28-year-old woman presents with a slow-growing, painless mass on the posterior aspect of her distal thigh. Radiographs demonstrate a heavily ossified, lobulated mass attached to the posterior cortex of the distal femur by a broad base, with a radiolucent 'string sign' visible between the tumor and the underlying bone. Which of the following molecular alterations is most characteristic of this tumor?

A 14-year-old boy presents with a 2-month history of worsening thigh pain, worse at night, and intermittent fevers. Radiographs show a permeative, destructive diaphyseal lesion with an 'onion-skin' periosteal reaction in the femur. Biopsy reveals small, round blue cells that strongly express CD99. Which of the following chromosomal translocations is most commonly associated with this patient's diagnosis?

A 19-year-old man presents with aching pain in his left mid-thigh that has been present for 6 months. The pain is characteristically worse at night and is dramatically relieved within 30 minutes of taking ibuprofen. CT scan demonstrates a 0.8 cm radiolucent nidus surrounded by dense reactive cortical sclerosis in the femoral diaphysis. The dramatic pain relief with NSAIDs is due to the inhibition of which of the following substances synthesized in high amounts by this lesion?

A 12-year-old girl presents with pain and swelling over her left proximal humerus after a minor fall. Radiographs show an expansile, eccentric, radiolucent lesion in the metaphysis. MRI demonstrates multiple internal fluid-fluid levels. Biopsy reveals blood-filled cystic spaces separated by fibrous septa containing osteoclast-like giant cells. Which of the following genetic alterations is most characteristic of the primary form of this lesion?

A 55-year-old man undergoes radiographs of his shoulder for rotator cuff symptoms, which incidentally reveal a 4 cm calcified lesion in the proximal humeral metaphysis. The calcifications are described as having a 'rings and arcs' appearance. Which of the following MRI findings would most strongly suggest a diagnosis of low-grade chondrosarcoma rather than a benign enchondroma?

A 10-year-old girl is evaluated for a leg length discrepancy and a limp. Radiographs of the left femur reveal a large medullary lesion with a 'ground-glass' appearance and a characteristic 'shepherd's crook' deformity of the proximal femur. She also has several large, irregular hyperpigmented macules on her back and signs of precocious puberty. Which of the following best describes the pathogenesis of her underlying condition?

A 15-year-old boy twists his ankle while playing basketball. Radiographs are negative for an acute fracture but incidentally demonstrate an eccentric, cortically based, well-circumscribed radiolucent lesion with a sclerotic margin in the distal tibial metaphysis. The lesion measures 3 cm in length. He has no pain localized to the site of the lesion itself. What is the most appropriate management of this incidental finding?

A 30-year-old woman presents with multiple asymmetric cartilaginous lesions in the short tubular bones of her hands and long bones, consistent with Ollier disease. What is the approximate lifetime risk of malignant transformation of these lesions, and what is the most common gene mutation associated with this condition?

A 16-year-old boy presents with severe, progressive right thigh pain that is worse at night and dramatically improves with ibuprofen. Radiographs show a thickened cortical diaphyseal area, and a CT scan

reveals a 7-mm radiolucent nidus with central calcification. What inflammatory mediator is found in high concentrations within the nidus of this lesion?

A 28-year-old man presents with a slow-growing, painful mass in his plantar foot. MRI reveals a soft tissue mass with heterogeneous signal intensity, and a core biopsy is performed. The diagnosis of synovial sarcoma is confirmed. Which of the following cytogenetic abnormalities is most characteristic of this tumor?

An asymptomatic 9-year-old boy undergoes a radiograph of his tibia after a minor contusion. The radiograph

reveals an eccentrically located, multilobulated, lytic lesion with a sclerotic rim in the distal tibial metaphysis. It measures 2 cm in length and occupies less than 20% of the bone diameter. What is the most appropriate management?