title: Signet-ring cell lymphoma of T-cell origin. An immunocytochemical and ultrastructural study relating giant vacuole formation to cytoplasmic sequestration of surface membrane.
abstract: In contrast to previous accounts of signet-ring lymphoma as a B-cell neoplasm, we report a case of signet-ring, large-cell lymphoma of T-cell lineage. Immunologic and ultrastructural studies were performed on a subcutaneous mass noted initially, as well as on an enlarged lymph node that developed later, in a 69-year-old man. Immunologic assessment indicated strong expression of T-helper antigen (Leu 3a + b), universal T-antigens (Leu 1, 5), and Ia. There was an absence of T-suppressor/cytotoxic antigen (Leu 2a), universal T-antigens (Leu 4, 9), and immunoglobulin light and heavy chains. Collectively, these findings indicate a mature T-cell lymphoma of T-helper type in an activated (Ia+) state. In contrast to previous reports of T-cell and Ia occurring solely as surface antigens, we demonstrated pools of cytoplasmic Leu 1, 3, 5 and Ia that displaced the nucleus. The ultrastructure of the giant cytoplasmic vacuoles was identical to the microvesicle-containing vacuoles reported in signet-ring cell lymphomas of B-cell lineage. In our case of T-cell lineage, we found substantial evidence of endocytosis by the neoplastic cells and numerous giant multivesicular bodies. The pools of cytoplasmic T and Ia antigens may result from abnormal internalization of surface T-antigens or the sequestration of T-antigen-containing Golgi-derived vesicles. Our combined immunologic and ultrastructural findings suggest that aberrant membrane recycling may be the common denominator of signet-ring formation in both B- and T-cell signet-ring lymphomas.
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D000368:Aged; D000911:Antibodies, Monoclonal; D001706:Biopsy; D003593:Cytoplasm / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D006651:Histocytochemistry; D006801:Humans; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D008223:Lymphoma / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D012540:Scapula; D012867:Skin / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D012878:Skin Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D014617:Vacuoles / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal