10. Pathology and Oncology MCQs

A 28-year-old man presents with an expansile, multiloculated radiolucent lesion in the metaphysis of his proximal tibia. MRI demonstrates multiple fluid-fluid levels. Biopsy reveals blood-filled spaces separated by fibrous septa containing reactive woven bone and osteoclast-like giant cells. A gene rearrangement involving which of the following loci is pathognomonic for this primary lesion?

A 65-year-old man presents with severe back pain and a destructive sacral mass. Biopsy reveals cords of large, vacuolated physaliferous cells in a myxoid stroma. The tumor cells are strongly positive for cytokeratin and S-100. Expression of which of the following immunohistochemical markers is most specific for confirming this diagnosis?

A 25-year-old male presents with a slowly enlarging mass on the plantar aspect of his foot. A biopsy reveals a biphasic tumor consisting of both spindle cells and epithelial cells forming gland-like structures. Which of the following chromosomal translocations is considered the pathognomonic driver for this tumor?

A 14-year-old boy complains of worsening left knee pain over 3 months. Radiographs demonstrate a 2 cm eccentric, well-circumscribed, lytic epiphyseal lesion with thin sclerotic margins in the proximal tibia. Histology shows mononuclear cells with grooved (coffee bean) nuclei and areas of fine, pericellular "chicken-wire" calcification. What is the most likely diagnosis?

A 16-year-old girl presents with a rapidly expanding, painful lesion in her distal femur. MRI reveals multiple fluid-fluid levels within an expansile cavity. Biopsy demonstrates blood-filled cavernous spaces lacking an endothelial lining, surrounded by septa containing fibroblasts and multinucleated giant cells. Primary lesions of this type are uniquely associated with a rearrangement of which gene?

A 55-year-old male presents with chronic lower back pain and new-onset bowel and bladder incontinence. Imaging reveals a large, destructive, midline sacral mass. Core needle biopsy shows a lobulated architecture with large cells containing highly vacuolated cytoplasm in a myxoid stroma. Which immunohistochemical marker is highly sensitive and specific for the suspected diagnosis?

A 60-year-old male with a history of hematuria presents with severe arm pain.

Radiographs show a large, destructive lytic lesion in the humeral diaphysis. A diagnosis of metastatic renal cell carcinoma is confirmed, and prophylactic internal fixation is planned. What is the most critical step prior to proceeding with surgical stabilization?

A 30-year-old male presents with a painful anterior shin.

Radiographs reveal a multicentric, eccentric "soap bubble" lytic lesion in the anterior tibial diaphysis. Biopsy demonstrates a biphasic tumor with nests of cytokeratin-positive epithelial cells intermixed within a bland fibrous stroma. What is the recommended definitive management?

A 22-year-old male with a known history of multiple palpable bone bumps since childhood notes recent rapid growth and pain originating from a protuberance on his distal femur. MRI reveals an exophytic mass with marrow continuity and a peripheral cartilage cap measuring 2.5 cm in thickness. Which of the following gene mutations is characteristic of his underlying syndrome?

A 35-year-old female presents with chronic, insidious swelling of her left knee and recurrent hemarthrosis despite no history of trauma. MRI displays extensive synovial thickening with a low signal intensity on T1 and T2, accompanied by severe blooming artifact on gradient-echo sequences. The pathogenesis of this condition involves a translocation resulting in the overexpression of which factor?

A 45-year-old male undergoes wide excision of a deep thigh mass. Histology demonstrates proliferating lipoblasts in a copious myxoid stroma with an intricate, arborizing "chicken-wire" capillary network. What specific cytogenetic abnormality defines this soft tissue sarcoma?

A 24-year-old male presents with dull, aching pain in his mid-back that awakens him at night. The pain is only partially relieved by NSAIDs. CT scan shows a 2.8 cm radiolucent, expansile lesion in the posterior elements of L3 with surrounding sclerosis. How does this lesion biologically differ most significantly from an osteoid osteoma?

A 24-year-old male presents with a slow-growing mass in the plantar aspect of his foot. Biopsy reveals a biphasic tumor with both epithelial and spindle cell components. Cytogenetic analysis reveals a t(X;18) translocation. Which of the following fusion genes is diagnostic of this patient's condition?

A 16-year-old boy presents with chronic knee pain. Radiographs show a well-circumscribed, eccentric, lytic lesion in the epiphysis of the proximal tibia. Biopsy demonstrates mononuclear cells, osteoclast-like giant cells, and a characteristic "chicken-wire" pattern of calcification. What is the most likely diagnosis?

A 9-year-old girl is evaluated for a limp and a leg length discrepancy. Physical examination reveals large, irregularly bordered cafe-au-lait spots. Radiographs of the femur demonstrate a "ground-glass" appearance and a "shepherd's crook" deformity. An activating mutation in which of the following genes is responsible for this condition?

A 65-year-old man presents with worsening back pain and fatigue. Radiographs show multiple punched-out lytic lesions in his skull and pelvis. Laboratory studies reveal hypercalcemia and anemia. A bone marrow biopsy would most likely show a proliferation of cells strongly positive for which of the following surface markers?

A 55-year-old man presents with bowel and bladder dysfunction alongside intractable sacral pain. Imaging reveals a destructive sacral midline mass.

Biopsy identifies large cells with vacuolated cytoplasm (physaliferous cells). Which immunohistochemical marker is highly sensitive and specific for confirming this diagnosis?

A 14-year-old girl presents with pain and swelling over her distal femur. Radiographs show an eccentric, expansile, lytic metaphyseal lesion. MRI demonstrates multiple fluid-fluid levels. Genetic analysis of this lesion would most likely show a rearrangement involving which of the following genes?

A 68-year-old man presents with a progressively enlarging, painful pelvic mass. Radiographs show a destructive lesion with intralesional "rings and arcs" calcifications.

Which of the following mutations is most frequently associated with this primary bone malignancy?