title: Differential diagnosis of Waldenstrom's macroglobulinemia and other B-cell disorders.
abstract: Waldenstrom's macroglobulinemia (WM) is characterized by lymphoplasmacytic infiltration of bone marrow and/or other tissues and by the presence of serum monoclonal immunoglobulin M ([IgM], without cutoff limit). Differential diagnosis from other B-cell disorders (BCDs) is usually easy based on clinical, morphologic, histopathologic, immunophenotypic, and genetic features. However, all BCDs potentially produce monoclonal IgM. In this study we reviewed the medical files of 130 patients with IgM-secreting BCDs. Eighty-four patients were diagnosed with WM, 5 with IgM-monoclonal gammopathy of undetermined significance (MGUS), and 41 with other BCDs (9 with B-cell chronic lymphocytic leukemia, 5 with small lymphocytic lymphoma, 14 with marginal zone lymphoma, 5 with mantle-cell lymphoma, 2 with follicular lymphoma, 2 with diffuse large B-cell lymphoma, 2 with cryoglobulinemia, and 2 with low-grade lymphoma not otherwise specified). Median IgM levels were 3215 mg/dL in WM, 840 mg/dL in IgM-MGUS, and 285 mg/dL in other BCDs (5 had IgM levels > 1500 mg/dL). In 10% of non-WM BCDs, monoclonal IgM was found only when more sensitive immunofixation methods were used. Forty-four percent of patients with BCDs (splenic marginal zone lymphoma or small lymphocytic lymphoma) had diagnoses that corresponded to that of WM. Careful diagnosis requires the concomitant evaluation of all parameters of BCDs together. Marginal zone lymphoma is the most frequently overlapping entity. Special attention should be given to mantle cell lymphoma in its atypical forms. Research in this field should continue to further clarify the disease entities that overlap with WM. New technology such as gene-expression profile techniques may contribute to this purpose.
authors.affiliation: First Department of Internal Medicine and Department of Hematology, National and Kapodistrian University of Athens, Laikon General Hospital, 16 Sevastoupoleos Street, Athens 11526, Greece. pangalis@med.uoa.gr
authors.forename: Gerassimos A
authors.initials: GA
authors.lastname: Pangalis
authors.forename: Maria-Christina
authors.initials: MC
authors.lastname: Kyrtsonis
authors.forename: Flora N
authors.initials: FN
authors.lastname: Kontopidou
authors.forename: Marina P
authors.initials: MP
authors.lastname: Siakantaris
authors.forename: Maria N
authors.initials: MN
authors.lastname: Dimopoulou
authors.forename: Theodoros P
authors.initials: TP
authors.lastname: Vassilakopoulos
authors.forename: Tatiana
authors.initials: T
authors.lastname: Tzenou
authors.forename: Styliani
authors.initials: S
authors.lastname: Kokoris
authors.forename: Evangelia
authors.initials: E
authors.lastname: Dimitriadou
authors.forename: Christina
authors.initials: C
authors.lastname: Kalpadakis
authors.forename: Kaliroe
authors.initials: K
authors.lastname: Tsalimalma
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Tsaftaridis
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Panayiotidis
authors.forename: Maria K
authors.initials: MK
authors.lastname: Angelopoulou
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis* / Q000276:immunology; D008223:Lymphoma / Q000175:diagnosis* / Q000276:immunology; D020522:Lymphoma, Mantle-Cell / Q000175:diagnosis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D008258:Waldenstrom Macroglobulinemia / Q000175:diagnosis* / Q000276:immunology
chemical_list: D007075:Immunoglobulin M