A 70-year-old man has fatigue, bone pain, and serum protein electrophoresis showing an IgG-kappa M-spike of 4.2 g/dL. Bone marrow biopsy shows 35% plasma cells. Serum calcium is 11.1 mg/dL and creatinine is 2.4 mg/dL. Skeletal survey reveals lytic lesions in skull and spine. According to IMWG 2014 criteria, this patient has:

• A Smouldering multiple myeloma requiring observation
• B MGUS (monoclonal gammopathy of undetermined significance)
• C Waldenström macroglobulinaemia
• D Active (symptomatic) multiple myeloma requiring treatment ✓

Explanation

IMWG 2014 criteria define active myeloma as ≥10% clonal marrow plasma cells (here 35%) plus ≥1 CRAB criterion: hyperCalcaemia (Ca >11 mg/dL — present), Renal insufficiency (creatinine >2 mg/dL — present), Anaemia, or Bone lesions (present). This patient has multiple CRAB features plus high plasma cell percentage, confirming active (symptomatic) MM requiring treatment. Smouldering MM has CRAB features absent and plasma cells 10–60% without myeloma-defining events. MGUS has <10% plasma cells and M-protein <3 g/dL.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.