title: IgM-producing gastric plasmacytoma.
abstract: A case of gastric plasmacytoma is reported in an 81-year-old woman. Immunofluorescent and immunoelectrophoretic studies showed that the tumor cells produced IgM-lambda molecules, whereas no monoclonal immunoglobulin could be detected both in the serum and in the urine. Of more than 60 reported cases of gastric plasmacytoma, only a few reports referred to the production of monoclonal immunoglobulin by the tumor cells. This case is the first one of IgM-producing gastric plasmacytoma. Moreover, the produced IgM was found to be 7S-IgM. It is extremely rare that 7S-IgM alone is detected in the absence of 19S-IgM.
mesh_terms: D000368:Aged; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007075:Immunoglobulin M / Q000096:biosynthesis*; D007146:Immunoglobulin lambda-Chains / Q000096:biosynthesis; D010954:Plasmacytoma / Q000276:immunology* / Q000473:pathology; D013274:Stomach Neoplasms / Q000276:immunology* / Q000473:pathology
chemical_list: D007075:Immunoglobulin M; D007146:Immunoglobulin lambda-Chains