A peculiar malformation of the upper lip: report of six cases.

Six cases of a peculiar type of upper lip malformation have been observed by the author during the last 40 years. The malformations in this case series were remarkably similar, suggesting a single teratologic entity not been reported before. The six patients included 1-, 11-, 4-, and 6-month-old males, a 20 year-old male, and an 11-year-old female. Each was characterized by a crooked folded philtrum, a flat thin vermilion region of the upper lip, and high-positioned ala(e), that was unilateral or bilateral. The upper median incisors were separated occasionally by the thick lip frenulum without marked distortion of the nasomaxillary framework. The author speculates that these cases exhibited some disturbed penetration of the lateral nasal eminence (process) to the median part of the nasolabial region in their early embryologic development.