Poorly differentiated carcinoma with neuroendocrine features in two patients with sinonasal tumours: a report of two cases.

Neuroendocrine tumors can be described as rare, heterogeneous, epithelial tumours with principally neuroendocrine differentiation that can be harboured in the sinonasal cavities. Owing to the intermingling of its clinical, radiological and histopathological features, the diagnosis of poorly differentiated sinonasal carcinomas with neuroendocrine features is a daunting one. Many of these tumours have a poor prognosis.