Immunohistochemical characterization of a B-cell signet ring cell lymphoma. Report of a case.

Signet ring cell lymphoma is a non-Hodgkin's lymphoma, characterized by neoplastic lymphoid signet ring cells very similar to epithelial mucin producing cells. We describe here a case of signet ring cell lymphoma in which the immunophenotypic markers of signet ring cells parallel those of plasma cells, being intensively T10+ (CD 38), weakly HLA-DR+, and To15 (CD 22) and T200 (CD 45) negative. The morphologic and immunohistochemical features of the case and the main differential diagnosis are preceded by a review of the literature.