Facial pain as a presenting symptom of a left maxillary sinus cyst: Case report and literature review.

Maxillary sinus retention cysts are typically benign, asymptomatic lesions that are discovered incidentally and rarely require intervention. We report a rare case of a 52-year-old male with a history of alcohol and tobacco use who presented with isolated, persistent midfacial pain without rhinologic, dental, or neurologic signs. Imaging revealed a large, expansile cystic lesion of the left maxillary sinus with extensive erosion of the sinus walls and extension into the infratemporal fossa, radiologically mimicking aggressive pathology such as mucocele, aneurysmal bone cyst, or malignancy. The patient underwent successful marsupialization via a modified Caldwell-Luc approach, with complete symptom resolution and no recurrence at 6 months. This case underscores the diagnostic challenges posed by atypical presentations of maxillary sinus retention cysts and highlights the importance of including such lesions in the differential diagnosis of destructive sinonasal masses, particularly when clinical and imaging features suggest a more aggressive process.