title: IgM multiple myeloma: disease definition, prognosis, and differentiation from Waldenstrom's macroglobulinemia.
abstract: IgM multiple myeloma (MM) and Waldenstrom's macroglobulinemia (WM) are two distinct hematologic entities with the common finding of an IgM monoclonal gammopathy. Distinguishing these two diagnoses is critical as the approach to therapy is different. A priori, we defined IgM MM as a symptomatic clonal plasma cell proliferative disorder characterized by an IgM monoclonal protein (regardless of size), 10% or more plasma cells on bone marrow biopsy, plus the presence of lytic bone lesions and/or translocation t(11;14). Twenty-one patients met this definition of IgM MM. All 21 patients had lytic bone lesions. Of the 16 evaluated with FISH, 6 (38%) demonstrated t(11;14). Median overall survival was 30 months, which is similar to non-IgM myeloma patients treated during this period and shorter than what would be expected for WM. In this, the largest series of patients with IgM MM, we describe the clinical features and prognosis of patient with IgM MM using a strict definition for the disease. The subset of patients without lytic lesions or t(11;14) but with immunophenotypic features suggestive of MM need further study.
authors.affiliation: Division of Hematology, Mayo Clinic Arizona, Scottsdale, AZ, USA. schuster.steven1@mayo.edu
authors.forename: Steven R
authors.initials: SR
authors.lastname: Schuster
authors.forename: Sundararajan Vincent
authors.initials: SV
authors.lastname: Rajkumar
authors.forename: Angela
authors.initials: A
authors.lastname: Dispenzieri
authors.forename: William
authors.initials: W
authors.lastname: Morice
authors.forename: Alvaro Moreno
authors.initials: AM
authors.lastname: Aspitia
authors.forename: Stephen
authors.initials: S
authors.lastname: Ansell
authors.forename: Robert
authors.initials: R
authors.lastname: Kyle
authors.forename: Joseph
authors.initials: J
authors.lastname: Mikhael
mesh_terms: D000368:Aged; D001847:Bone Diseases; D001853:Bone Marrow / Q000473:pathology; D002999:Clone Cells / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007075:Immunoglobulin M; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis*; D011379:Prognosis; D015996:Survival Rate; D014178:Translocation, Genetic; D008258:Waldenstrom Macroglobulinemia / Q000175:diagnosis*
chemical_list: D007075:Immunoglobulin M