A 58-year-old asymptomatic man is found to have 20% monoclonal plasma cells on bone marrow biopsy and an IgG kappa M-protein of 3.4 g/dL. Hemoglobin 12.5 g/dL, corrected serum calcium 9.2 mg/dL, creatinine 0.9 mg/dL, skeletal survey shows no lytic lesions, and no end-organ damage is identified. What is the correct diagnosis and management implication?

• A Smoldering myeloma; close observation without immediate therapy ✓
• B Active multiple myeloma; immediate induction chemotherapy
• C MGUS; annual monitoring only, no marrow follow-up needed
• D Solitary plasmacytoma; local radiotherapy

Explanation

Smoldering myeloma requires clonal bone marrow plasma cells of 10 to 60 percent plus a serum M-protein of at least 30 g/dL, in the absence of CRAB features or myeloma-defining events. This patient meets both thresholds but has no end-organ damage, so observation with surveillance is standard unless high-risk biomarkers are present. MGUS requires less than 10 percent plasma cells and M-protein below 30 g/dL, both exceeded here.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.