[Carcinoma with predominant lymphoid stroma in hepatobiliary system--report of 2 cases].

Lymphoepithelioma-like carcinoma (LELC) is an undifferentiated carcinoma with predominant lymphocytic infiltration, which is associated with Epstein-Barr virus (EBV) in variable proportions. We report two cases of carcinoma with predominant lymphoid stroma in hepatobiliary system. The first case was a lymphoepithelioma-like undifferentiated carcinoma with focal differentiation of cholangiocarcinoma (cytokeratin 19+) and hepatocellular carcinoma in light microscopy. The infiltration of CD8+ T lymphocytes was observed in the tumor and the surrounding hepatic parenchyme. In this tumor, EBV was detected and LMP1 was positive immunohistochemically. The second case showed the mixed features of lymphoepithelioma-like carcinoma and cholangiocarcinoma with predominant lymphoid stroma. In this case, EBV was detected. LELC of hepatobiliary system is an entity distinguished from conventional carcinoma with lymphoid stroma, and its association with EBV warrants further research.