A case of necrotizing sialometaplasia in the upper lip.

Necrotizing sialometaplasia is a benign, reactive, and self-limiting inflammatory disorder with clinical and histologic features resembling carcinoma. A fifty-eight-year-old woman presented with a firm submucosal mass on the right side of the upper lip, measuring 0.5 cm. Histopathologic examination of the incisional biopsy specimen was reported as adenoid cystic carcinoma, resulting in removal of the mass with a large excision and reconstruction of the primary site. However, final histopathologic diagnosis of the excised mass was necrotizing sialometaplasia. No recurrences occurred during a three-year follow-up. This report draws attention to the difficulty in distinguishing between necrotizing sialometaplasia and adenoid cystic carcinoma.