A case of an epidermoid cyst arising in the maxillary sinus

In the oral and maxillofacial regions, epidermoid cysts usually develop in the floor of the mouth and rarely in other sites. We describe a case of an epidermoid cyst arising in the right maxillary sinus. A 27-year-old man was referred to our department for swelling in the right buccal region. Computed tomography showed a dense soft-tissue mass that extended widely into the maxillary sinus, resulting in thinning of the cortical bone of the exterior wall of the maxillary sinus. The cyst was enucleated via the intraoral approach with the patient under general anesthesia. Histopathologically, the wall was lined with a thin layer of keratinizing squamous epithelium and fibroma connective tissue with no skin appendages. The diagnosis was an epidermoid cyst. There has been no evidence of recurrence during the 3-year follow-up.