Lymphoepithelioma-like carcinoma of the lung: analysis of two cases for Epstein-Barr virus infection.

Lymphoepithelioma-like carcinoma, which is an uncommon histological type of epithelial tumor, has been described as being closely associated with Epstein-Barr virus (EBV) infection in organs other than the lung. Recently, we experienced two surgically resected cases of pulmonary tumors mimicking lymphoepithelioma-like carcinoma. Both cases contained EBV DNA genomes as shown by polymerase chain reaction (PCR) using EBV DNA-specific primers, one positive for EBV DNA in virtually all cancer cells, and the other showing positive hybridization in a small number of cancer cells by in situ hybridization (ISH) using digoxigenin-labeled olignucletide probes for each of EBV DNA for EBV DNA. EBV-encoded RNA-1 (EBER-1) was typically detected in one case. These results are highly suggestive of EBV-associated tumors in one of the current cases, although in the other case, no such close association was determined. It seems that lymphoepithelioma-like pulmonary carcinoma, which seems extremely unusual, may be closely associated with EBV infection in tumorigenesis.