title: Systemic CD5+ MALT lymphoma: presentation with Waldenstrom syndrome.
abstract: We report a case of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) in a 75-year-old woman with a neuropathy related to high levels of serum immunoglobulin M and a history of rheumatoid arthritis and polymyositis. The patient developed a mass in the right submandibular salivary gland, and this mass demonstrated histopathologic features that are typical of MALT lymphoma, including infiltrates of small monocytoid B cells in the epithelium (forming "lymphoepithelial lesions"), a reactive background of florid germinal center hyperplasia, and follicular colonization by the monocytoid B cells. Many plasma cells in the background expressed cytoplasmic immunoglobulin M lambda, matching the serum spike. Flow cytometric analysis confirmed the presence of clonal mature B cells; however, unlike most MALT lymphomas, these cells coexpressed dim CD5. Clinical staging revealed evidence of systemic distribution with documented disease involving the bone marrow, the lung, and a paratracheal lymph node. Analysis of this unusual systemic MALT lymphoma, and a comparison with similar examples from the literature, illuminates relationships among MALT lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, and Waldenstrom macroglobulinemia.
authors.affiliation: Department of Pathology, Case Western Reserve University, Pathology Institute, Cleveland, OH 44106, USA. imikoles@aol.com
authors.forename: Irina
authors.initials: I
authors.lastname: Mikolaenko
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Listinsky
mesh_terms: D000368:Aged; D001402:B-Lymphocytes / Q000473:pathology; D018956:CD5 Antigens / Q000378:metabolism*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D018442:Lymphoma, B-Cell, Marginal Zone / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D010523:Peripheral Nervous System Diseases / Q000150:complications / Q000175:diagnosis / Q000473:pathology; D012468:Salivary Gland Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D013577:Syndrome; D008258:Waldenstrom Macroglobulinemia / Q000097:blood / Q000150:complications / Q000175:diagnosis*
chemical_list: D018956:CD5 Antigens; D007075:Immunoglobulin M