Undifferentiated gastric carcinoma with lymphoid stroma (lymphoepithelioma-like carcinoma/medullary carcinoma).

Undifferentiated gastric carcinoma with lymphoid stroma is a histological type of gastric cancer with favourable prognosis, microscopically characterised by nests of neoplastic epithelial cells intermingled with a dense lymphoid proliferation. Various studies have shown a close relationship between undifferentiated gastric carcinoma with lymphoid stroma and Epstein-Barr virus infection; the presence of viral DNA in tumour cell nuclei has been demonstrated using polymerase chain reaction and Epstein-Barr virus-encoded small RNA in neoplastic cell nuclei have been found using in situ hybridization. We describe two cases of undifferentiated gastric carcinoma with lymphoid stroma, one infiltrating the submucosa of the gastric body and the other invading the muscularis propria of the antrum. No lymph node neoplastic invasion was documented in either case. Epstein-Barr virus was detected in the neoplastic cell nuclei in both cases with in situ hybridization.