Midline sinuses of the upper lip. Case report.

Nine midline sinuses of the upper lip in eight patients have been described previously. They have been located from the skin under the columella to the frenulum, and have always been directed towards the frenulum. Three new cases are presented: a sinus reaching from the skin of the philtrum to the frenulum in a child with Pierre Robin syndrome, another one in the frenulum of a patient with two separate midline sinuses of the nose, and a third in the frenulum of a child with a partial median cleft lip. The midline sinus is probably caused by disturbed development of the nasofrontal process. The combination of upper lip sinus and Pierre Robin's syndrome is hardly coincidental and supports the concept that the latter is not caused solely by a foetal malposition.