RESUMO
Neuroendocrine carcinomas are epithelial neoplasm with predominant neuroendocrine differentiation. Mostly they are found in gastrointestinal and respiratory system. In the nasal and paranasal sinus regions, squamous cell carcinoma is the most common tumor, followed by adenocarcinoma, malignant lymphoma, sinonasal undifferentiated carcinoma, and olfactory neuroblastoma. Large cell neuroendocrine carcinoma of head and neck region is extremely rare. Until now, very few cases of neuroendocrine tumors of paranasal sinuses have been documented. Compared to other organ systems, the neuroendocrine carcinoma involving sinuses are much more aggressive and with poor prognosis. The rarity of this carcinoma has restricted the understanding of its etiology and clinical outcome. We herein reporting a case of large cell poorly differentiated neuroendocrine tumor of maxilla with orbital extension with the purpose of analysis of the available information of this rare malignancy.