Epidemiology of Multiple Myeloma and Related Disease

Plasma cell disorders include monoclonal gammopathies of undetermined significance (MGUS), smoldering/indolent myeloma, and active myeloma. Related disorders are Waldenstrom’s macroglobulinemia, the heavy-chain diseases, primary systemic amyloidosis, and systemic light-chain deposition disease. The characteristic feature of these diseases is the involvement of cells that are either plasma cells or lymphocytes resembling plasma cells and typically the production of immunoglobulin (Ig) (heavy and/or light chains) in a monoclonal fashion. The most common myelomas are IgG or IgA κ or λ, and κ or λ Bence Jones-only myeloma. Waldenstrom’s macroglobulinemia is IgM κ or λ in type.