Coexistence of Epstein-Barr virus-associated gastric carcinoma with malignant lymphoma: report of two cases.

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBV-GC) is not rare, accounting for 5 to 18% of all gastric carcinomas. Recently, we encountered two cases of EBV-GC of ordinary histopathological type coexistent with malignant lymphoma. One patient was a 71-year-old Japanese man who had two lesions, one in the cardia and the other in the antrum of the stomach. The former was EBV-GC without lymphoma, and antral one was EBV-GC with diffuse large B-cell lymphoma (DLBCL). The other patient was a 49-year-old Japanese man who had received chemotherapy for pelvic DLBCL 3 years earlier. He had EBV-GC with follicular lymphoma in the fundus of the stomach. In both cases, gastric carcinomas were positive for EBV-encoded small RNA by in situ hybridization, whereas the lymphoma cells, infiltrating nonneoplastic lymphocytes, and nonneoplastic epithelial cells were negative. The present cases suggest that focal immunosuppression by adjacent gastric lymphomas might be related to the alteration of the microenvironment and development of EBV-GC.