PRIMARY GASTRIC T-CELL LYMPHOMA WITH AND WITHOUT HUMAN T-LYMPHOTROPICVIRUS TYPE-1

BACKGROUND. Gastric T-cell lymphomas are rare, and their incidence and viral status have not yet been fully clarified. METHODS. Sixty-seven cases of surgically resected gastric lymphomas from city hospitals in Tokyo were evaluated. The surface phenotype was determined by immunohi stochemistry, gene rearrangement by Southern blot hybridization, asso ciation with Epstein-Barr virus (EBV) by EBV-encoded small RNAs in sit u hybridization, and the presence of human T-cell lymphotropic virus t ype 1 (HTLV-1) by serology, Southern blot hybridization, and polymeras e chain reaction analysis. RESULTS. Five of the 67 cases were T-cell l ymphoma (7%): 3 cases were HTLV-1 negative (-) and 2 were HTLV-1 posit ive (+). Systemic eosinophilia was observed in the three HTLV-1(-) gas tric lymphomas. Neoplastic cells were morphologically similar in both groups, but a granulomatous reaction with marked eosinophilia was obse rved only in the two cases of HTLV-1(-) lymphoma. They also had charac teristics of natural killer (NK) cell-like T-cell lymphoma, expressing NK markers and TCR gamma gene rearrangement. Positivity with HML-1 (s pecific for intestinal epithelial T-cells lymphoma was observed in one HTLV-1(+) lymphoma. The EBV gene was detected in only one case of B-c ell lymphoma but not in any case of T-cell lymphoma. CONCLUSIONS. Gast ric T-cell lymphoma occurs in 7% of gastric lymphomas in Japan and is comprised of HTLV-1-related lymphomas and lymphomas unrelated to HTLV- 1, including NK cell-like lymphomas with eosinophilia. (C) 1997 Americ an Cancer Society.