Sinonasal non-small cell neuroendocrine carcinoma the validity of histological grading: Case report and a review of the literature

Introduction: Paucity of reported cases and lack of significant follow-up preclude definitive statements regarding the prognosis of sinonasal non-small cell neuroendocrine carcinoma (NSNEC). The validity of histologic grading as a prognostic indicator in sinonasal NSNEC is also not known. Case report: We present a case of a primary moderately differentiated neuroendocrine carcinoma (atypical carcinoid tumor) that showed unilateral involvement of the nasal cavity, maxillary sinus and sphenoid sinus. The tumor cells displayed fairly uniform round to oval stippled nuclei with abundant granular, eosinophilic cytoplasm. There was positivity for neuroendocrine and epithelial markers. The patient underwent surgery with post-operative adjuvant radiotherapy. There has been no recurrence or distant metastasis in the 93-months since the patient's initial presentation. Conclusion: The role of histologic subtyping and grading as a potential prognostic indicator within the sinonasal family of neuroendocrine tumors is discussed. Keywords: Neuroendocrine carcinoma, Non-small cell neuroendocrine carcinoma, Paranasal sinu