10. Pathology and Oncology MCQs

An asymptomatic 35-year-old woman has a hand radiograph taken after a minor sprain, revealing the lesion shown.

Recent molecular studies show that solitary lesions of this type are most strongly associated with somatic mutations in which of the following genes?

A 24-year-old male presents with a painless palpable mass on the proximal humerus. Radiographs show a surface-based radiolucent lesion with a well-defined sclerotic border and overhanging cortical edges. Which of the following radiographic features best differentiates this lesion from a juxtacortical (periosteal) chondrosarcoma?

A 15-year-old girl is undergoing post-treatment surveillance following wide resection and neoadjuvant chemotherapy for conventional osteosarcoma of the distal femur. What is the most common site of metastasis for this tumor and the primary imaging modality for surveillance?

A 55-year-old man undergoes a biopsy of a large destructive pelvic mass. Histopathology reveals Grade 2 conventional chondrosarcoma. Staging studies are negative for metastasis. What is the most appropriate primary treatment?

A 40-year-old man with Multiple Hereditary Exostoses presents with a newly enlarging mass on his right posterior distal femur. MRI reveals an exophytic bone lesion with an overlying hyperintense cartilaginous cap on T2-weighted images. What cartilage cap thickness is highly suspicious for secondary malignant transformation?

A 42-year-old woman presents with persistent hip pain. Radiographs demonstrate an expansile, lytic epiphyseal lesion in the proximal femur with sharp margins. Histologic evaluation shows cells with abundant clear cytoplasm and distinct cell membranes intermixed with areas of reactive bone formation. What is the most likely diagnosis?

A 14-year-old boy is diagnosed with Ewing sarcoma of the femoral diaphysis. Staging is performed. The presence of metastasis at diagnosis is the most significant negative prognostic factor. Which of the following are the two most common sites of metastasis for this disease?

A 65-year-old male presents with a pathologic fracture of the humerus through a purely lytic, highly destructive lesion. Staging reveals an unknown primary tumor. Before planning an open biopsy, standard practice requires a CT of the chest, abdomen, and pelvis. Which primary carcinoma is notorious for producing highly vascular lytic metastases that may require pre-operative embolization?

A 60-year-old woman presents with thigh pain. Radiographs show a centrally located lesion in the distal femur with rings and arcs of calcification, alongside a large, destructive, purely lytic unmineralized mass breaching the cortex. Biopsy confirms a bimorphic histologic pattern. What is this entity?

A 20-year-old male presents with chronic knee pain. Imaging reveals an eccentric, purely lytic lesion in the proximal tibial metaphysis with a well-demarcated sclerotic margin. Histology shows lobules of stellate and spindle-shaped cells in a myxoid background, with an increased concentration of cells at the periphery of the lobules. What is the diagnosis?

A 16-year-old female is diagnosed with osteosarcoma of the distal femur. A full-length MRI of the entire femur is ordered prior to finalizing surgical planning. What is the primary purpose of imaging the entire involved bone?

A 32-year-old female presents with a surface-based lesion on the posterior distal femur measuring 6 cm. It lacks a sunburst appearance or medullary involvement. Biopsy reveals Grade 2 cartilaginous tissue without malignant osteoid. How does the management of this periosteal chondrosarcoma differ from that of periosteal osteosarcoma?

A 35-year-old man undergoes knee arthroscopy for mechanical catching. The surgeon finds dozens of white, cartilaginous loose bodies of similar size within the joint space, and the synovium appears thickened. What is the estimated risk of malignant transformation of this condition?

Which of the following histologic factors correlates most strongly with long-term survival in a patient undergoing treatment for localized conventional osteosarcoma?

A 22-year-old patient presents with a painful mass on the proximal phalanx. Radiographs show a small saucerized surface lesion with a sclerotic margin.

Biopsy confirms a periosteal chondroma. The pain persists despite conservative measures. What is the definitive management?

A 10-year-old child presents with a permeative lesion in the diaphysis of the fibula with an 'onion-skin' periosteal reaction. A core needle biopsy demonstrates sheets of small round blue cells. Which chromosomal translocation is the diagnostic hallmark for the most likely tumor?

A 45-year-old woman is evaluated for a large, purely lytic sacral lesion. Biopsy shows large cells with abundant clear cytoplasm and distinct borders. Immunohistochemistry is strongly positive for cytokeratin and EMA. What is the most likely diagnosis?

A 50-year-old male is being treated for a low-grade central chondrosarcoma of the proximal femur. Which of the following imaging features on MRI is most characteristic of high-grade transformation or dedifferentiation within a pre-existing low-grade cartilage tumor?

A 15-year-old female presents with multiple hard bony swellings on her hands and bluish, compressible soft tissue nodules on her forearms. Which of the following describes the underlying genetic abnormality and the estimated lifetime risk of malignant transformation in this patient?

A 14-year-old boy completes neoadjuvant chemotherapy and wide resection for a distal femur osteosarcoma. Two years later, a surveillance chest CT reveals three new, unilateral peripheral lung nodules (largest 1.5 cm) with no other evidence of disease. What is the most appropriate next step in management?