A 70-year-old man has smouldering multiple myeloma. His serum free light chain ratio (involved/uninvolved) is 110. According to IMWG 2014 criteria, this alone defines progression to:
- A Active multiple myeloma requiring treatment ✓
- B MGUS requiring watchful waiting only
- C Waldenstrom macroglobulinemia
- D Light chain amyloidosis requiring organ biopsy
Correct answer: A. Active multiple myeloma requiring treatment
Explanation
The 2014 IMWG criteria introduced three biomarkers as myeloma-defining events (MDEs) independent of CRAB features: clonal bone marrow plasma cells ≥60%, serum FLC ratio ≥100 (involved/uninvolved), and >1 focal lesion on MRI. A serum FLC ratio of 110 (>100) meets an MDE criterion and mandates initiating treatment as active myeloma, even without CRAB end-organ damage. This patient no longer meets criteria for smouldering myeloma watchful waiting.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.