10. Pathology and Oncology MCQs

A 30-year-old male presents with chronic anterior knee pain and intermittent swelling. MRI reveals a nodular intra-articular mass with low signal intensity on both T1 and T2 weighted sequences, along with blooming artifact on gradient-echo imaging. Histology shows mononuclear cells, multinucleated giant cells, and hemosiderin-laden macrophages. Which of the following drives the pathogenesis of this lesion?

A 35-year-old male presents with an anterior shin mass. Radiographs show a multiloculated, expansile, eccentric radiolucency in the anterior cortex of the tibial diaphysis. Histology exhibits a biphasic pattern of uniform epithelial cells forming nests and tubules within a bland spindle-cell fibrous stroma. Which immunohistochemical stain will best differentiate the prominent cell nests in this tumor from surrounding osteofibrous tissue?

A 25-year-old woman presents with a deep, firm mass in her plantar fascia. Excisional biopsy reveals nests of pale, uniform cells separated by delicate fibrous septa. Immunohistochemistry is strongly positive for S100, HMB-45, and Melan-A. Cytogenetics reveals a t(12;22)(q13;q12) translocation. What is the diagnosis?

A 22-year-old male presents with a slowly growing, ulcerating nodule on his volar wrist. It was initially excised at an outside clinic under the assumption it was a necrotizing granuloma, but it rapidly recurred. Histology shows epithelioid cells arranged in nodules with central necrosis. Which immunohistochemical finding is a diagnostic hallmark of this malignancy?

A 35-year-old female presents with a painless mass on the posterior aspect of her distal femur. Imaging shows a densely ossified mass attached to the cortex with a broad base, showing no medullary involvement. Biopsy reveals well-formed trabeculae of mature woven bone within a bland, low-grade spindle cell stroma. Which genetic alteration is characteristic of this lesion?

A 16-year-old boy presents with pain in his shoulder. Radiographs show an epiphyseal lytic lesion in the proximal humerus with subtle internal calcifications. Biopsy demonstrates mononuclear cells with longitudinal nuclear grooves and areas of eosinophilic matrix with a 'chicken-wire' pattern of calcification. What genetic mutation is specifically associated with this tumor?

A 45-year-old man presents with a large, painless mass in his deep thigh musculature. MRI demonstrates a lipomatous tumor with thick, nodular septations. Histologic examination reveals mature adipocytes alongside atypical, hyperchromatic spindle cells. Which molecular finding confirms the diagnosis of Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma?

A 15-year-old male presents with a rapidly enlarging mass in his forearm. Biopsy reveals a primitive malignant neoplasm with small round blue cells arranged in clusters separated by dense fibrous septa, forming cleft-like spaces. Immunohistochemistry is strongly positive for desmin and myogenin. Which translocation is most likely present?

A 10-year-old girl is evaluated for multiple bony deformities and multiple dark, compressible soft tissue masses on her hands. Radiographs reveal numerous cartilaginous lesions within the medullary canals of the phalanges, and multiple phleboliths in the adjacent soft tissues. This patient is at a significantly increased risk for which of the following complications?

A 24-year-old female presents with a destructive, lytic lesion in her distal femur. Biopsy shows an intraosseous proliferation of uniform, bland spindle cells with abundant collagen bundles, resembling a soft-tissue desmoid tumor. There is no cytological atypia or pleomorphism. This lesion is most commonly associated with mutations in which of the following genes?

A 70-year-old man with advanced prostate cancer develops new, diffuse osteoblastic metastases in his lumbar spine and pelvis. The mechanism of this profound osteoblastic response is primarily mediated by the secretion of which of the following factors by the metastatic tumor cells?

A 40-year-old male presents with a deep mass in his thigh. Histology reveals a pattern of atypical spindle cells arranged in a 'staghorn' or hemangiopericytoma-like vascular pattern, interspersed with thick bands of collagen. Immunohistochemistry demonstrates strong nuclear expression of STAT6. What is the most likely diagnosis?

A 25-year-old male presents with a deep, painless mass in his posterior thigh. MRI shows a well-circumscribed soft tissue mass adjacent to the knee joint. Biopsy reveals a biphasic tumor consisting of epithelial cells forming glandular structures and a spindle cell stromal component. Which of the following chromosomal translocations is diagnostic for this malignancy?

A 14-year-old boy presents with chronic shoulder pain. Radiographs reveal a well-defined, lytic epiphyseal lesion in the proximal humerus with a sclerotic margin. Biopsy shows mononuclear cells with grooved nuclei and areas of "chicken-wire" calcification. Which of the following genetic mutations is most characteristic of this lesion?

A 40-year-old male undergoes excision of a large thigh mass. Histopathological examination demonstrates a multinodular tumor with a myxoid stroma, scattered lipoblasts, and a prominent "chicken-wire" capillary network. Which translocation drives the pathogenesis of this tumor?

A 10-year-old girl is evaluated for a limp. Radiographs show a "shepherd's crook" deformity of the proximal femur with a ground-glass appearance. Biopsy reveals curvilinear woven bone trabeculae lacking osteoblastic rimming set in a fibrous stroma. A mutation in which of the following genes is responsible for this condition?

A 22-year-old male presents with a firm, ulcerating nodule on the volar aspect of his right wrist. Biopsy demonstrates nodular proliferations of epithelioid and spindle cells with central areas of necrosis, mimicking a granuloma. Which of the following immunohistochemical or molecular findings is most specific for this diagnosis?

A 15-year-old boy presents with progressive distal femur pain. Radiographs show a sclerotic metaphyseal lesion with a "sunburst" periosteal reaction. Biopsy confirms pleomorphic cells producing malignant osteoid. The patient's family history is significant for multiple early-onset cancers. A germline mutation in which gene is most likely present?

A 60-year-old male presents with progressive constipation and urinary incontinence. Imaging reveals a large, destructive midline mass involving the sacrum. Biopsy demonstrates lobules of vacuolated cells with a bubbly appearance embedded in a myxoid stroma. Which of the following immunohistochemical markers is most specific for this tumor?

A 30-year-old female presents with a slowly enlarging mass on her plantar foot deep to the plantar fascia. Biopsy shows nests of uniform cells with clear cytoplasm and prominent nucleoli, divided by fibrous septa. Immunohistochemistry is strongly positive for HMB-45 and S-100. Which chromosomal abnormality is diagnostic?