title: Differential diagnosis of IgM MGUS and WM according to B-lymphoid infiltration by morphology and flow cytometry.
abstract: The distinction between IgM monoclonal gammopathy of undetermined significance (MGUS), asymptomatic Waldenstrom's macroglobulinemia (WM; aWM), and symptomatic WM (sWM) relies on two features: the presence of infiltration by lymphoplasmacytic lymphoma in the bone marrow (BM) biopsy and the existence of signs or symptoms attributable to the disease. Nevertheless, some patients lack a BM biopsy or it is not conclusive for diagnosis. In this study we have investigated 94 patients with IgM monoclonal gammopathies, in which a BM trephine biopsy and morphological and flow cytometry (FCM) evaluation of BM aspirate were available at diagnosis. We found a clear correlation between BM infiltration of B-lymphocytes assessed by morphology and by FCM with a Pearson correlation of 0.62 (P<.001). Moreover, in the absence of a BM trephine biopsy, the cut-off points that would help in the differential diagnosis between MGUS, aWM, and sWM would be 20% for morphology and 5% for FCM, both assessed in the BM aspirate.
authors: University Hospital of Salamanca, Cancer Research Center (IBMCC-CSIC), University of Salamanca, Spain. emocio@usal.es
authors: Enrique M
authors: EM
authors: Ocio
authors: Daniel
authors: D
authors: del Carpio
authors: Álvaro
authors: Á
authors: Caballero
authors: Jennifer
authors: J
authors: Alonso
authors: Bruno
authors: B
authors: Paiva
authors: Roberto
authors: R
authors: Pesoa
authors: Teresa
authors: T
authors: Villaescusa
authors: Lucía
authors: L
authors: López-Anglada
authors: Belén
authors: B
authors: Vidriales
authors: Ramón
authors: R
authors: García-Sanz
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology*; D008297:Male; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D008258:Waldenstrom Macroglobulinemia / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
chemical_list: D007075:Immunoglobulin M