We report an extremely rare case of a large solitary fibroma of the paranasal sinus, which we treated by sinonasal endoscopic surgery. We describe its clinical and histopathological features, and we report the endoscopic technique used to deal with such a large sinonasal mass (penetrating the pterygomaxillary and infratemporal fossae); we also offer a brief survey of the literature.

A woman presented with an approximately one-year history of nasal obstruction. Nasal endoscopy revealed an irregularly shaped, friable, reddish mass that occupied the whole of the right nasal fossa. Magnetic resonance imaging of the paranasal sinuses revealed a large mass that occupied the anterior and posterior ethmoids and the maxillary and sphenoid sinuses, displacing the septum and penetrating the pterygomaxillary fossa, having destroyed the lateral wall of the right nasal fossa. The tumour was resected by means of sinonasal endoscopic surgery; an endoscopic medial maxillectomy with extension to the pterygomaxillary and infratemporal regions was performed. Histological analysis confirmed the diagnosis of solitary fibrous tumour. During follow up, we performed regular nasal endoscopies, as well as computed tomography scans one and six months post-operatively.

Endoscopic techniques are currently the approach of choice for the treatment of such tumours of the sinonasal cavity and pterygomaxillary and infratemporal regions. The size of the lesion did not contraindicate endoscopic sinonasal surgery as a curative treatment.