Neuroendocrine neoplasms of the sinonasal region.

Abstract

Neuroendocrine neoplasms of the sinonasal region, which are relatively uncommon but clinically very important, are reviewed here in the light of current knowledge. Using a definition for neuroendocrine based on phenotypic, histologic, immunohistochemical, and electron microscopic features rather than histogenetic criteria, sinonasal neuroendocrine carcinomas are examined with a particular emphasis on the small-cell and large-cell subtypes. This is followed by revisiting olfactory neuroblastoma because it is also a tumor that shows a neuroendocrine phenotype. Kadish clinical and Hyams histologic grading systems as prognosticators of olfactory neuroblastoma are also considered in detail. Finally, controversies regarding sinonasal undifferentiated carcinoma as a neuroendocrine tumor are discussed and a possible relationship with high-grade olfactory neuroblastoma is explored. Genetic events and current management of these tumors are also outlined. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2259-E2266, 2016.