Neoplasia USMLE Step 1 Practice Question
A 63-year-old woman with a 15-year history of Paget disease presents with acute left leg pain, swelling, and immobility. Vital signs: BP 128/82, HR 92, RR 16, Temp 37.2°C, SpO2 98%. Physical examination reveals a firm, warm tibial mass. Biopsy demonstrates malignant spindle cells with marked nuclear atypia and abundant osteoid formation. Alkaline phosphatase is elevated at 320 U/L. She denies recent trauma or constitutional symptoms. Which complication of chronic Paget disease explains this sarcomatous transformation?
Answer choices
- ASpinal cord compression from vertebral expansion
- BHyperparathyroidism-induced hypercalcemia
- CPathologic fracture with secondary infection
- DMalignant transformation to osteosarcomaCorrect answer
- EAneurysmal bone cyst formation
- FChronic osteomyelitis from pagetic bone resorption
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