Hematologic Malignancies USMLE Step 1 Practice Question
A 42-year-old woman presents to the emergency department with progressive fatigue over 3 months and severe lower back pain unresponsive to NSAIDs. She reports no weight loss, fever, or night sweats. Vital signs are stable (BP 128/82, HR 92, RR 18, Temp 37.2°C). Laboratory studies show hemoglobin 9.5 g/dL, creatinine 1.9 mg/dL (baseline unknown), calcium 11.8 mg/dL, and albumin 3.2 g/dL. Serum protein electrophoresis demonstrates no monoclonal spike. Urine protein electrophoresis shows no Bence Jones proteins. Bone marrow biopsy reveals 35% clonal plasma cells. Skeletal survey shows multiple lytic lesions. Which of the following diagnoses best explains these clinical and laboratory findings?
Answer choices
- AMonoclonal gammopathy of undetermined significance (MGUS)
- BWaldenstrom macroglobulinemia
- CLight chain myeloma (nonsecretory on serum, secretory on urine)Correct answer
- DSymptomatic multiple myeloma with IgG monoclonal protein
- ETrue nonsecretory myeloma
- FAL amyloidosis without plasma cell myeloma
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