Extramedullary plasmacytomas are localized tumours formed of monoclonal plasma cells in an extra-skeletal area. They constitute approximately 3% of all neoplasms originating from plasma cells. They generally display a destructive course. When the literature in English was reviewed, only 19 cases with the primary disease localized in the sphenoid sinus were found. We present the case of a 50-year-old male patient who presented with gradually increasing visual loss over 6 weeks, whose radiological tests revealed a formation of mass in the sphenoid sinus pressing against the optic nerve and internal carotid artery. A biopsy obtained by endoscopic sinus surgery was reported to be a plasmacytoma. A diagnosis of extramedullary plasmacytoma was made after investigations for other neoplastic plasma cell conditions proved negative. Extramedullary plasmacytomas were assessed by reviewing the literature. (C) 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.