Waldenstrom macroglobulinemia

Waldenstrom macroglobulinemia A rare, chronic low-grade and slow-growing malignancy of plasma cells. These plasma cells multiply out of control, invade the bone marrow, lymph nodes, and spleen, and characteristically produce huge amounts of the antibody macroglobulin (IgM). The excess IgM causes the blood to thicken. Waldenstrom macroglobulinemia can occur in younger people but is usually seen in people over age 65. See also lymphoma; plasma cell.