Huge sphenoid sinus olfactory neuroblastoma: a case report.

Intranasal or paranasal sinus olfactory neuroblastoma is a rare malignant neoplasm of olfactory neuroepithelial origin, accounting for approximately 5% of paranasal sinus cancers. Most of the presenting symptoms include nasal obstruction, nasal bleeding, anosmia, rhinorrhea, and headache. In this present report, we describe a 79-year-old man who presented with bilateral nasal congestion for more than 1 year. Nasoendoscopy showed a huge, smooth, mucosal tumor in the nasopharynx with extension to the posterior nasal septum. The tumor was completely resected under endonasal endoscopy and the pathology revealed olfactory neuroblastoma. Olfactory neuroblastomas usually arise in the cribriform plate and superior turbinate. However, the origin and isolation of olfactory neuroblastomas to the sphenoid sinus is exceedingly rare. Only four cases of olfactory neuroblastoma isolated in the sphenoid sinus have been described in English literature and the frequency of presenting symptoms with cranial neuropathies and headache. We report a case of primary sphenoid sinus olfactory neuroblastoma with the greatest enlargement reported to date.