Midline congenital upper lip sinus: a rare clinical case with analytical review of diagnostic and therapy strategies

Shuang Yang¹Kai Kang²Wei Liu^2*Zhibo Zhou^1*

• ¹Peking University School and Hospital of Stomatology, Beijing, China
• ²The First Hospital of China National Pharmaceutical Group (Yiji Hospital), Baotou, China

Congenital lip sinus, which may sometimes present merely as a superficial lip pit, is an exceptionally rare congenital malformation1. Clinically, the lower lip sinus is the most commonly observed form, with a reported incidence of 0.001% in the general population2. Its prevalence is even lower among Caucasians, approximately 0.00001%, while data on its occurrence in other ethnic groups remain scarcely documented, lower lip sinuses may occur in isolation or be associated with various syndromes, such as Van der Woude syndrome3. The incidence of upper lip sinus is even lower than that of lower lip sinus. The first case of congenital upper lip sinus was reported by Holbrook in 1970 4. Clinically, the opening of an upper lip sinus is typically located in the philtrum, with the sinus tract directed toward the labial mucosa and usually not communicating with the oral cavity 5. Some literature has also reported that the blind end of the sinus tract may extend as far as the bony surface of the anterior nasal spine6. Upper lip sinus may be associated with other midline anomalies, including double frenulum, frenulum sinus, nasal dermoid cyst, and hypertelorism7. Due to its extremely low incidence and limited clinical reports, this article presents a Chinese pediatric case of congenital upper lip sinus (a rare subtype with ethnic and age characteristics) and reviews the existing literature to provide reference for clinical practitioners.