Sinonasal malignancies of neuroendocrine origin.

The sinonasal malignancies of putative neuroendocrine origin-esthesioneuroblastoma, sinonasal neuroendocrine carcinoma, sinonasal undifferentiated carcinoma, and sinonasal small cell carcinoma-are uncommon malignancies that frequently present with locally advanced disease. Pathologic distinction between these entities can be difficult, but is important to guide management. These malignancies require complex multimodality treatment and are best managed by multidisciplinary teams in major centers that have expertise in sinonasal malignancies.