Macroglobulinemia (Primary Macroglobulinemia; Waldenström Macroglobulinemia) By James R Berenson, MD, Institute for Myeloma and Bone Cancer Research Reviewed / Revised Jun 2023 View Patient Education Symptoms and Signs Diagnosis Treatment Key Points Macroglobulinemia is a malignant plasma cell disorder in which B cells produce excessive amounts of IgM M-proteins.