A Case of Congenital Midline Sinus of the Upper Lip.

Congenital lip sinus is known to occur in the upper lip, lower lip, or oral commissure, but a midline sinus of the upper lip is extremely rare. This report describes a 5-year-old boy who was born as a dizygotic twin at a gestational age of 33 weeks and 6 days, weighing 2,118 g. He was noted at birth to have a subcutaneous mass with an opening in the philtrum of the upper lip. Magnetic resonance imaging at 1 year of age revealed a teardrop-shaped cyst with high intensity on T2-weighted images beneath the upper lip. Surgical excision was performed due to the gradual enlargement of the mass. The sinus tract was removed using a combined intraoral and extraoral approach. Histopathology showed cystic dilation of the epithelial lining. The postoperative course was uneventful with good aesthetic results. Early diagnosis and excision are essential for the successful management of this rare congenital anomaly.