10. Pathology and Oncology MCQs

A 55-year-old man presents with chronic, progressively worsening thigh pain. Radiographs demonstrate a large radiolucent lesion with 'popcorn' calcifications in the proximal femur and prominent endosteal scalloping. Histological evaluation shows lobules of hyaline cartilage with atypical, binucleated cells within lacunae. What is the most important histologic predictor of prognosis and metastasis for this patient's lesion?

A 30-year-old woman presents with a slow-growing, painful mass around her ankle. Imaging reveals an extra-articular soft-tissue mass with stippled calcifications. Biopsy demonstrates a biphasic pattern consisting of both epithelial and spindle cells. Cytogenetic testing of the lesion is most likely to reveal which of the following translocations?

A 60-year-old man presents with bowel and bladder dysfunction and sacral pain. MRI shows a destructive, lobulated mass centered in the sacrum. Histopathology shows lobules of myxoid tissue containing large cells with vacuolated cytoplasm (physaliferous cells). Immunohistochemistry for this tumor will characteristically be positive for cytokeratin, EMA, S-100, and which of the following highly specific markers?

A 24-year-old man presents with a nodular lesion on the volar aspect of his finger that has slowly ulcerated, mimicking a chronic infection or granuloma. Biopsy reveals epithelioid and spindle cells arranged in a nodular pattern with central necrosis. Immunohistochemistry demonstrates a loss of SMARCB1 (INI1) expression. What is the most likely diagnosis?

A 28-year-old female presents with a palpable, painless mass on the posterior aspect of her distal thigh. Radiographs demonstrate a dense, lobulated, ossified mass attached to the posterior cortex of the distal femur with a 'string sign' (radiolucent cleft). Biopsy confirms a low-grade spindle cell stroma interspersed with well-formed woven bone trabeculae. Which genetic alteration is characteristic of this tumor?

A 12-year-old girl is evaluated for a pathological fracture of the proximal femur. Radiographs reveal a large, diaphyseal expansile lesion with a 'ground-glass' matrix and a 'shepherd's crook' deformity. A biopsy shows irregular, C-shaped trabeculae of woven bone lacking prominent osteoblastic rimming in a fibrous stroma. What is the underlying molecular mechanism of this disorder?

A 45-year-old man undergoes excision of a large, deep soft-tissue mass in his thigh. Pathology reveals a uniform proliferation of primitive mesenchymal cells, small signet-ring lipoblasts, and a prominent plexiform ('chicken-wire') capillary network within a myxoid stroma. Which cytogenetic abnormality is pathognomonic for this tumor?

A 32-year-old man presents with chronic anterior tibial pain. Radiographs show a multiloculated, eccentric, osteolytic lesion in the anterior diaphysis of the tibia. Histopathology demonstrates a biphasic tumor with nests of basaloid epithelial cells surrounded by an osteofibrous stroma. Immunohistochemistry is positive for broad-spectrum cytokeratins. What is the most likely diagnosis?

A 5-year-old boy presents with anterior bowing of the tibia. Imaging shows a radiolucent, intracortical lesion along the anterior tibial diaphysis. Biopsy reveals fibroblastic tissue with trabeculae of woven bone that are characteristically rimmed by active, plump osteoblasts. Cytokeratin staining is negative. Patients with this condition require clinical follow-up primarily to monitor for progression into which of the following entities?

A 40-year-old man presents with hip pain. Radiographs reveal a well-defined lytic lesion in the epiphysis of the proximal femur. Biopsy demonstrates sheets of cells with abundant, clear cytoplasm and distinct cell membranes, interspersed with areas of woven bone and chondroid matrix. What is the most appropriate management for this lesion?

A 68-year-old man presents with severe back pain and fatigue. Radiographs show multiple punched-out lytic lesions in his skull and vertebrae. Laboratory studies reveal hypercalcemia and a monoclonal spike on serum protein electrophoresis. A bone marrow biopsy confirms the diagnosis. Which immunohistochemical marker is characteristically strongly positive on the neoplastic cells?

A 35-year-old woman presents with chronic knee swelling, pain, and catching. MRI demonstrates a large, nodular intra-articular mass with dark signal intensity on T1 and T2-weighted images due to hemosiderin deposition. A biopsy confirms tenosynovial giant cell tumor (pigmented villonodular synovitis). What is the underlying molecular pathogenesis driving the proliferation of this lesion?

A 4-year-old boy presents with a painful, lytic lesion in the skull vault. Biopsy demonstrates a proliferation of mononuclear histiocyte-like cells with grooved, 'coffee-bean' nuclei, admixed with eosinophils. Electron microscopy identifies characteristic tennis-racket-shaped cytoplasmic organelles. Recent targeted therapies for this disease successfully inhibit which of the following commonly mutated kinases?

A 6-year-old girl presents with a rapidly expanding soft tissue mass in her forearm. Biopsy reveals sheets of primitive small round blue cells with prominent fibrovascular septa lacking central cellularity, creating an 'alveolar' pattern. Strong desmin and myogenin positivity is noted. Which specific chromosomal translocation is most frequently identified in this malignancy?

A 28-year-old male presents with a slowly enlarging, painless mass around his ankle. MRI shows a soft tissue mass adjacent to the Achilles tendon. Core biopsy reveals a biphasic tumor with both epithelial-like glandular structures and uniform spindle cells. Which of the following cytogenetic abnormalities is pathognomonic for this tumor?

A 65-year-old man presents with dull pelvic pain. Radiographs reveal a bulky, destructive lesion in the ilium with 'ring-and-arc' calcifications. Biopsy demonstrates atypical chondrocytes with binucleation and permeation of the host trabecular bone. Mutations in which of the following genes are most frequently implicated in the pathogenesis of this primary bone tumor?

A 55-year-old woman complains of chronic sacral pain and bowel dysfunction. MRI shows a midline, destructive sacral mass. Biopsy reveals lobules of large, vacuolated cells with bubbly cytoplasm arranged in a myxoid stroma. Immunohistochemistry is positive for S100, cytokeratin, and a highly specific nuclear transcription factor. What is this specific immunohistochemical marker?

A 6-year-old boy presents with back pain. Radiographs demonstrate vertebra plana of T8. A biopsy of the vertebral body shows a proliferation of mononuclear cells with folded, 'coffee-bean' nuclei, admixed with numerous eosinophils. These neoplastic cells are most likely to harbor a mutation in which of the following?