Pneumosinus dilatans of the maxillary sinus: a case report and review of the literature.

Pneumosinus dilatans (PSD) is an abnormal dilatation of one or more of the paranasal sinuses and must be included in the differential diagnosis of expansile lesions of the sinonasal tract. The frontal and sphenoid sinuses are the most frequently involved sites. Herein, we present the case of a 30-year-old woman with a 6-year history of right nasal obstruction and pain in the right maxillary region, elicited by rapid changes in atmospheric pressure. Computed tomography (CT) detailed an abnormal expansion of the right maxillary sinus resulting from a process of hyperpneumatization with no evidence of bone erosion, leading to the diagnosis of PSD. Restoration of permanent pressure equilibrium in the right maxillary sinus and improvement in the patency of the nasal fossa were achieved by a subtotal resection of the medial wall of the maxillary sinus by an endoscopic approach. Two years later, the patient was asymptomatic, and a CT scan showed no progression of the disease.