IgM Monoclonal Gammopathy of Undetermined Significance

**Semantic type:** Neoplastic Process

**Definition:** Monoclonal gammopathy of undetermined significance defined by a serum IgM paraprotein concentration less than 30g/L; bone marrow lymphoplasmacytic infiltration of less than 10%; and no evidence of anemia, constitutional symptoms, hyperviscocity, lymphadenopathy, hepatosplenomegaly, or other end-organ damage that can be attributed to the underlying lymphoproliferative disorder. It is a precursor condition that may progress to lymphoplasmacytic lymphoma/ Waldenstrom macroglobulinemia, other B-cell neoplasms, or primary amyloidosis. Progression to plasma cell myeloma occurs rarely, if at all. (WHO 2017)

**Synonyms:** - IgM MGUS