Congenital sinus of the upper lip is extremely rare and only 3 cases have been reported domestically. We report a case of congenital sinus of midline upper lip, which was found in an adolescent patient.

A 14-year-old girl presented with a small pit on midline of the upper lip, which was visible at birth. The patient had never been treated for the congenital sinus because it was asymptomatic. Surgical excision under local anesthesia was performed.

The sinus had a tract extending into 5 mm posteroinferior and had not penetrated the oral cavity. Histological examination showed a fistulous tract lined by keratinized squamous epithelium. After complete excision, there was no recurrence and we obtained a satisfactory cosmetic result.

Congenital sinus of the midline upper lip is extremely rare. This is a special case that is reported because it did not cause symptoms for the patient until she reached adolescence.