Monophasic epithelial synovial sarcoma accompanied by an inverted papilloma in the sphenoid sinus.

A 58-year-old man presented with a six-month history of intermittent blood-stained posterior nasal discharge. Five years ago, he had a three-week episode of fitful light headaches. Nasal ventilation, olfactory sensation, and facial sensation were normal; there were no ophthalmological complaints. Coronal computed tomography (CT) scans revealed soft masses in the bilateral sphenoid sinuses with bone absorption. The patient underwent bilateral functional endoscopic sinus surgery and resection of right nasal papillary masses. Papillary masses and mucosa in both sphenoid sinuses were also removed. The mass in the left sphenoid sinus was diagnosed as two separate entities, one being a primary monophasic epithelial synovial sarcoma and the other an inverted papilloma, while the mass in the right sphenoid sinus was an inverted papilloma. After surgery, the patient underwent radiotherapy and chemotherapy. At the 50-month follow-up visit, there were no signs of recurrence.