OBJECTIVE: The undifferentiated carcinoma of the type lymphoepithelial is a type rare of the neoplasias of nasopharynx, related with the Epstein-Barr virus. This work tells a case of patient with immunohistochemical diagnosis of this carcinoma. CASE REPORT: Masculine patient, 31 years, taken care of carrier of chronic rhinosinusitis with complaint of nasal blockage has 30 days with purulent rhinorrhea and cervical tumor-like has 15 days. TC of face with result of mucous thickening of SSMM and veiling of ethmoids. To the nasofibroscopy examination, injury of polypoid aspect obliterating FFNN, purulent secretion and malodorous odor. Submitted to the polypectomy and excision of the left cervical node. The histopathological demonstrated to compatible neoplasm with lymphoma classic Hodgkin with mixing cells, however the immunohistochemistry of lymphoma showed positivity for the markers LMP1, protein viral (EBV) oncogenic and cytokeratin, compatible with undifferentiated carcinoma of the type lymphoepithelial, suggesting primary place of nasopharynx and association with EBV. Discussion: The carcinomas of nasopharynx are related with the race, being more prevalent in Asians. The story shows the importance of it diagnosis differential for detention of undifferentiated carcinoma of the type lymphoepithelial, being the most indicated the immunohistochemistry. The expression for LMP1, viral protein (EBV) oncogenic, indicates narrow relation of the EBV with etiopathogenesis of this undifferentiated carcinoma.