Isolated midline upper lip pit.

To cite: Hili S, Wong KY, Goodacre T. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2016215496 DESCRIPTION A fit and well 7-year-old girl presented with an asymptomatic isolated midline upper lip pit (figure 1). This was not associated with cleft lip or palate. Examination revealed no other congenital abnormalities. There was no significant family history. The pit was treated successfully with excision. Intraoperatively, a fistula probe was inserted via the cutaneous opening of the pit, which confirmed no intraoral communication. The entire sinus tract was then excised and the wound directly closed. Histology revealed irregular pilosebaceous units with some fibrous scarring in the upper dermis. Congenital pits are some of the most uncommon developmental malformations of the lip. Lower lip pits are commonly associated with cleft lip and/or palate in Van der Woude syndrome. The latter can present with a range of other anomalies such as hypodontia, syndactyly and congenital heart defects. Upper lip pits tend to be non-syndromic epigenetic malformations. Associations with other midline deformities, including double frenulum, sinus of the frenulum, nasal dermoid cyst and hypertelorism have also been described. Conversely, only around 18 cases of isolated upper lip pits have been reported. The mechanisms involved in congenital upper lip sinus formation are incompletely understood. Three main proposals have been suggested including invagination theory, merging theory and fusion theory. Lip pits can present as asymptomatic irregularities of the lip or with recurrent discharge or infection. Examination usually reveals a depression in the vermilion zone of the lip and opening into a blind sinus. Most cases can be treated by simple excision via an intraoral or extraoral approach.