According to current International Myeloma Working Group criteria, which combination correctly defines smouldering multiple myeloma?
- A Bone marrow clonal plasma cells 12%, serum M-protein 35 g/L, creatinine 1.0 mg/dL, calcium 9.2 mg/dL, normal skeletal survey ✓
- B Serum M-protein 15 g/L, bone marrow clonal plasma cells 8%, and one lytic lesion on MRI
- C Bone marrow clonal plasma cells 65%, serum free light chain ratio 100, and hypercalcemia of 11.8 mg/dL
- D Serum M-protein 20 g/L, bone marrow clonal plasma cells 5%, and urine Bence Jones proteinuria of 500 mg/day
Correct answer: A. Bone marrow clonal plasma cells 12%, serum M-protein 35 g/L, creatinine 1.0 mg/dL, calcium 9.2 mg/dL, normal skeletal survey
Explanation
Smouldering multiple myeloma requires clonal bone marrow plasma cells of 10 percent or more, or a serum M-protein of 30 g/L or more, with absence of CRAB features and amyloid-related organ damage. Option A meets both thresholds with entirely normal end-organ parameters. Option B falls below both numeric cut-offs, option C has hypercalcemia making it overt myeloma, and option D fails both quantitative thresholds despite significant light chain excretion.
Reference: Williams Hematology, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.