IgM myeloma and Waldenstrom's macroglobulinemia: a distinct clinical feature, histology, immunophenotype, and chromosomal abnormality.

Multiple myeloma represents a malignant proliferation of plasma cells derived from a single clone within the bone marrow. While the cause of myeloma is not known, interleukin 6 may play a role in driving myeloma cell proliferation. Waldenstrom's macroglobulinemia (WM) is a proliferative disease of B-lymphocytes. The cells have lymphoplasmacytoid features and secrete IgM. It is important to distinguish between IgM myeloma and WM as they have distinct clinical courses and prognoses, and treatment strategies are therefore different. The clinical characteristics of a patient diagnosed with IgM myeloma, and his excellent response to treatment are reported here.