10. Pathology and Oncology MCQs

A 55-year-old male presents with a large pelvic mass. Biopsy demonstrates atypical chondrocytes with binucleation and myxoid stroma, consistent with a high-grade conventional chondrosarcoma. What is the most appropriate primary treatment modality?

An 18-year-old male complains of severe nocturnal thigh pain that is completely relieved by ibuprofen. Radiographs show a 1.0 cm radiolucent nidus surrounded by dense reactive sclerosis in the femoral diaphysis. The intense pain is pathogenically caused by the secretion of which substance by the nidus?

A 55-year-old man undergoes wide resection of a large, painful cartilaginous tumor of the proximal humerus. Histopathology reveals a conventional grade II chondrosarcoma. Which of the following metabolic gene mutations is most frequently implicated in the pathogenesis of this specific tumor?

A 10-year-old girl is evaluated for a severe shepherd's crook deformity of the proximal femur and precocious puberty. Radiographs show extensive 'ground-glass' opacities in the affected bone. The pathogenesis of her underlying musculoskeletal condition is directly related to which of the following molecular mechanisms?

A 14-year-old boy complains of intense thigh pain that worsens at night and is dramatically relieved by ibuprofen. Imaging reveals a 1 cm radiolucent nidus surrounded by dense sclerotic bone in the proximal femur. Which of the following biochemical mediators is secreted in excess by the central nidus?

A 28-year-old man presents with a slow-growing, painful mass near his knee joint. MRI shows a well-circumscribed, lobulated mass in the popliteal fossa with calcifications. Biopsy reveals a biphasic proliferation of spindle cells and epithelial cells. Which chromosomal translocation is highly diagnostic for this tumor?

An 8-year-old girl is found to have an expansile, eccentric lytic lesion in the metaphysis of her distal radius. MRI demonstrates multiple fluid-fluid levels within the lesion. Genetic analysis of the primary lesion would most likely reveal a translocation leading to the upregulation of which of the following genes?

A 62-year-old man with a history of nephrectomy for renal cell carcinoma presents with a solitary lytic metastasis in the proximal femur causing an impending pathologic fracture. Prior to prophylactic internal stabilization, which adjunctive intervention is most critical to minimize perioperative surgical morbidity?

A 35-year-old woman presents with a slow-growing mass on the anterior aspect of her tibia. Radiographs show a distinct eccentric 'soap bubble' lytic lesion in the anterior tibial diaphysis. Histology reveals biphasic nests of epithelial cells surrounded by a bland fibrous stroma. Which immunohistochemical marker will predictably be strongly positive in the epithelial component?

A 14-year-old boy presents with chronic knee pain. Radiographs reveal a 2 cm eccentric, purely lytic lesion located entirely within the distal femoral epiphysis. Biopsy demonstrates mononuclear cells and areas of chondroid matrix with fine, 'chicken-wire' calcifications. Which of the following genetic mutations is most strongly associated with this lesion?

A 25-year-old woman presents with progressive right hip pain and a noticeable limp. Radiographs demonstrate a 'shepherd's crook' deformity of the proximal femur with a hazy, ground-glass matrix in the medullary canal. Which of the following underlying molecular defects is responsible for this condition?

A 60-year-old man presents with a destructive lytic lesion in his humeral diaphysis. Biopsy reveals nests of clear cells with abundant cytoplasm. He has a known history of radical nephrectomy. What is the most appropriate next step prior to prophylactic surgical fixation of the humerus?

A 16-year-old boy presents with a rapidly expanding, painful lytic lesion in the proximal humerus. MRI demonstrates a multiloculated lesion with prominent fluid-fluid levels. Biopsy confirms a primary aneurysmal bone cyst (ABC). Which genetic abnormality is the primary driver of this true neoplasm?

A 25-year-old man presents with a slowly enlarging, painful mass near his knee joint. Radiographs show a soft tissue mass with stippled calcifications. Biopsy demonstrates a biphasic tumor with both spindle cells and epithelial-like cells. Which of the following chromosomal translocations is characteristic of this malignancy?

A 65-year-old man presents with severe back pain, anemia, and hypercalcemia. Radiographs show multiple punched-out lytic skull lesions. A Technetium-99m bone scan is performed but fails to demonstrate increased uptake in the areas of destruction. What is the primary reason for this false-negative bone scan?

A 28-year-old woman presents with a painless mass on the posterior aspect of her distal femur. Radiographs demonstrate a dense, lobulated, broad-based ossifying mass on the cortical surface with a 'string sign' separating part of the tumor from the cortex. There is no medullary involvement. Which genetic alteration is characteristic of this lesion?

A 30-year-old man presents with a swelling on his lower leg. Radiographs reveal an eccentric, multilobulated lytic lesion in the anterior diaphyseal cortex of the tibia. Histologic evaluation shows nests of epithelial cells within a benign fibrous stroma. Which of the following is the most likely diagnosis?

A 9-year-old boy presents with mild shoulder pain after throwing a baseball. Radiographs reveal a centrally located, purely lytic lesion in the proximal humeral metaphysis. A small cortical fragment is seen resting at the dependent portion of the radiolucent cavity. What is the most likely diagnosis?