According to current diagnostic criteria, which combination correctly defines smoldering (asymptomatic) multiple myeloma?
- A Any M-protein level with lytic bone lesions but no hypercalcemia or renal failure
- B Serum M-protein less than 3 g/dL and clonal plasma cells less than 10 percent, with normal free light chain ratio
- C Serum M-protein 3 g/dL or greater and/or clonal bone marrow plasma cells 10 percent to 60 percent, without any myeloma-defining event ✓
- D Clonal plasma cells above 60 percent with suppressed uninvolved immunoglobulins
Correct answer: C. Serum M-protein 3 g/dL or greater and/or clonal bone marrow plasma cells 10 percent to 60 percent, without any myeloma-defining event
Explanation
Smoldering myeloma requires an M-protein of at least 3 g/dL and/or 10 to 60 percent clonal marrow plasma cells in the absence of CRAB features, amyloidosis, or other biomarkers of malignancy such as free light chain ratio above 100, more than 60 percent plasma cells, or focal MRI lesions. Option B describes MGUS, option A describes active myeloma because lytic lesions alone define malignancy, and option D is already active myeloma by the 60 percent rule.
Reference: Williams Hematology, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.