Hematologic Malignancies USMLE Step 1 Practice Question
A 68-year-old man with a 20 pack-year smoking history presents with hemoptysis, dyspnea, and constitutional symptoms. Chest imaging reveals a left upper lobe mass with mediastinal lymphadenopathy. Bronchoscopy with biopsy confirms small cell lung cancer (SCLC). Laboratory evaluation shows WBC 3,500/μL (reference 4,500-11,000), hemoglobin 9.2 g/dL, and platelets 95,000/μL. Peripheral blood smear shows 2% circulating blasts. Flow cytometry is performed to evaluate for concurrent hematologic malignancy. Which of the following findings would most strongly suggest a clonal hematologic process rather than reactive cytopenia from paraneoplastic or toxic effects?
Answer choices
- ACD34+ cells comprise 3% of total WBC with polyclonal immunoglobulin light chain expression
- BAbsolute neutropenia with preserved monocyte and lymphocyte percentages
- CCD34+ cells comprise 8% of total WBC with clonal T-cell receptor gene rearrangementCorrect answer
- DCD13+ and CD33+ myeloid markers with abnormal maturation and increased myeloid blasts
- EMild reduction in CD8+ T cells with oligoclonal T-cell receptor pattern
- FNormal B and T cell populations with polyclonal light chain restriction
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