General Pathology USMLE Step 1 Practice Question
A 55-year-old man presents with progressive fatigue and recurrent bacterial infections. Vital signs: BP 128/82, HR 92, RR 16, Temp 37.2°C, SpO2 98%. Physical examination reveals moderate splenomegaly; lymphadenopathy is absent. CBC demonstrates pancytopenia (WBC 3.2K, Hgb 9.1, Plt 85K). Bone marrow aspiration yielded minimal material; biopsy reveals abnormal lymphocytes with characteristic hair-like cytoplasmic projections. Which histochemical stain is classically positive in this disorder?
Answer choices
- AVimentin only
- BPSA
- CChromogranin
- DTRAPCorrect answer
- EDesmin
- FAcid phosphatase resistant to tartrate inhibition
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