Undifferentiated carcinoma of the nasopharynx and leukemoid reaction: report of case with literature review.

A case of undifferentiated carcinoma of the nasopharynx presenting as a cervical mass associated with a paraneoplastic neutrophilic leukemoid reaction is reported. The diagnosis of undifferentiated nasopharyngeal carcinoma of the Regaud type was established by the presence of aggregates of epithelial neoplastic cells separated by areas of reactive lymphoid cells; the epithelial nature being confirmed by the positivity for epithelial markers (AE1/AE3, EMA). Serum IL-1a, GM-CSF and TNF alpha remained undetectable suggesting that these factors were not involved in the occurrence of the paraneoplastic leukemoid syndrome.