A rare case of lymphoepithelial carcinoma of the lip.

Lymphoepithelial carcinoma (LEC) is a rare category of malignant neoplasms that share morphologic features with undifferentiated nasopharyngeal carcinoma, which can be regarded as the prototype Epstein-Barr virus (EBV)-positive epithelial neoplasm. A similar association with EBV is emerging for LEC of the oral cavity, which appears to be strongly influenced by the ethnic origin of the patient. A rare case of primary LEC of the lower lip in a 73-year-old Caucasian man is described. The tumor showed a striking microscopic resemblance to undifferentiated nasopharyngeal carcinoma (lymphoepithelioma) with features of a syncytial growth pattern, large undifferentiated tumor cells with vesicular nuclei, prominent eosinophilic nucleoli, and a dense intratumoral lymphocytic infiltrate. There was, however, no evidence of EBV infection of the tumor cells by immunohistochemistry and polymerase chain reaction, suggesting that EBV probably does not play a role in the pathogenesis of LEC of the lip in Caucasian patients.