Primary small cell undifferentiated (neuroendocrine) carcinoma of the maxillary sinus.

Primary small cell undifferentiated (neuroendocrine) carcinomas of the paranasal sinuses are extremely uncommon neoplasms. This tumor was first reported in this site in 1965, and since then there have been only 61 documented cases in the literature. The median age at presentation is 53 years, with no gender predilection. There is no reported association of occurrence of this tumor with either tobacco use or form of occupation, and case outcome is usually poor. We report a case in a 25-year-old man, initially treated as an odontogenic infection and thus delaying institution of appropriate management. Further investigation identified a locally advanced neuroendocrine carcinoma of the left maxilla. Despite radiotherapy and chemotherapy, the patient exhibited rapid tumor dissemination and died.