[Atypical involvement of undifferentiated carcinomas of the nasopharyngeal type. Apropos of 3 cases].

We report 3 cases of undifferentiated carcinomas of nasopharyngeal type (UCNT) found in unusual sites and compare them with histologically identical tumors found in the nasopharynx. Using viral serology and viral marquers found in the tumor cells, we looked for a link with the Epstein Barr Virus (EBV) which exists in the nasopharyngeal site. It appears that UCNT found in unusual sites have a poorer prognostic than the same nasopharyngeal tumors; no link was found with EBV. The number of published cases is too small to form a conclusion, therefore, we propose a systematic search for EBV, presenting our protocol, each time is discovered UCNT in an unusual site.