Congenital midline sinus of the upper lip is a rare disease; a search of world literature revealed that only 32 cases have been reported. A case of a 41-year-old man with a frequently recurring congenital sinus at the columellar base is presented. There are several hypotheses on the etiology of this condition: A defect of fusion of the facial process in utero, a failure of downgrowth of the nasofrontal process, excessive furrowing of the philtrum, and the formation of a false nasal cavity. The location of the orifice in previously reported sinuses has been examined and is discussed. [ABSTRACT FROM AUTHOR]