What is multiple myeloma?

Both criteria must be met: 1. Clonal bone marrow plasma cells ≥10% or biopsy-proven bony or extramedullary plasmacytoma 2. Any one or more of the following myeloma defining events: – Evidence of end organ damage that can be attributed to the underlying plasma cell proliferative disorder, specifically: hypercalcemia >0.25 upper limit, anemia, renal insufficiency, bone lesions by PET – Clonal bone marrow plasma cell percentage ≥60% – Involved: uninvolved serum free light chain (FLC) ratio ≥100 (involved free light chain level must be ≥100 mg/L) – >1 focal lesions on magnetic resonance imaging (MRI) studies (at least 5mm in size)