Plasma Cell Dyscrasias

Multiple Myeloma (MM)

Definition and epidemiology (NEJM 2011;364:1046)

  • Malignant neoplasm of plasma cells producing a monoclonal Ig = “M protein
  • ~27,000 new cases/y; median age at diagnosis 69 y; more common in African Americans

Clinical manifestations (CRAB criteria and other less common features)

  • HyperCalcemia due to ↑ osteoclast activity
  • Renal disease: multiple mechanisms include toxic effect of filtered light chains → renal failure (cast nephropathy) or type II RTA; amyloidosis or light chain deposition disease → nephrotic syndrome; hypercalcemia, urate nephropathy, type I cryoglobulinemia
  • A