title: Waldenstrom macroglobulinemia involving extramedullary sites: morphologic and immunophenotypic findings in 44 patients.
abstract: Waldenstrom macroglobulinemia (WM) is a clinicopathologic syndrome in which a B-cell neoplasm involving the bone marrow, usually lymphoplasmacytic lymphoma (LPL), is associated with immunoglobulin M paraprotein in the serum. Extramedullary involvement occurs in a subset of patients and is infrequently examined histologically. The files of M.D. Anderson Cancer Center were searched for patients with WM who underwent biopsy of one or more extramedullary sites during the course of disease. Each biopsy specimen was classified using the criteria of the World Health Organization classification. The study group consisted of 44 patients (26 men and 18 women), with a total of 51 specimens obtained from lymph nodes (n = 36), soft tissue (n = 4), spleen (n = 3), skin (n = 2), lung (n = 2), tonsils (n = 1), colon (n = 1), liver (n = 1), and gallbladder (n = 1). Lymphoplasmacytic lymphoma was the most common histologic type, in 40 (78%) samples. This category was morphologically heterogeneous and was further subclassified as lymphoplasmacytic (n = 21), lymphoplasmacytoid (n = 18), and polymorphous (n = 1). Four of these LPL cases morphologically resembled marginal zone B-cell lymphoma. Four additional samples were involved by diffuse large B-cell lymphoma, probably transformed from LPL. Three more samples were involved by LPL with unusual features: two were CD5-positive and one was a composite tumor with classical Hodgkin's disease. Other categories of lymphoma in this group of patients with WM included small lymphocytic lymphoma/chronic lymphocytic leukemia (n = 2), mantle cell lymphoma (n = 1), and follicular lymphoma (n = 1). Waldenstrom macroglobulinemia is most commonly associated with LPL but can rarely occur with other types of B-cell lymphoma. Lymphoplasmacytic lymphoma in patients with WM is morphologically heterogeneous and can be indistinguishable from marginal zone B-cell lymphoma. CD5+ B-cell lymphomas with features otherwise typical of LPL are rare, and we think these tumors are part of the spectrum of LPL.
authors.affiliation: Department of Hematopathology, University of Texas, MD Anderson Cancer Center, Houston, Texas 77030, USA. peilin@mdanderson.org
authors.forename: Pei
authors.initials: P
authors.lastname: Lin
authors.forename: Carlos
authors.initials: C
authors.lastname: Bueso-Ramos
authors.forename: Carla S
authors.initials: CS
authors.lastname: Wilson
authors.forename: Adnan
authors.initials: A
authors.lastname: Mansoor
authors.forename: L Jeffrey
authors.initials: LJ
authors.lastname: Medeiros
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007150:Immunohistochemistry; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications / Q000276:immunology / Q000473:pathology*; D008221:Lymphoid Tissue / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008258:Waldenstrom Macroglobulinemia / Q000209:etiology / Q000276:immunology / Q000473:pathology*
chemical_list: D015415:Biomarkers; D007075:Immunoglobulin M