Isolated lower lip fistula

Isolated lower lip fistula, also known as congenital lower lip pits or congenital lip fistulae, is a rare developmental anomaly characterized by the presence of bilateral or unilateral sinuses (pits or fistulae) on the vermilion border of the lower lip. These pits represent blind-ending or mucous gland-connected tracts that may intermittently discharge saliva or mucus. The condition is present at birth and is considered a congenital malformation of the lip. Unlike Van der Woude syndrome, in which lip pits occur alongside cleft lip and/or cleft palate, isolated lower lip fistula occurs without any associated cleft anomalies or other syndromic features. The condition primarily affects the oral and facial structures. The lip pits are typically symmetrical, located on either side of the midline of the lower lip, and may appear as small depressions or elevated nodules. While the condition is generally benign and does not cause significant functional impairment, the pits can be cosmetically concerning and may occasionally become infected or cause discomfort due to mucous discharge. In some cases, the fistulae connect to minor salivary glands beneath the lip mucosa. Treatment is primarily surgical and is pursued for cosmetic reasons or to address recurrent mucous discharge or infection. Surgical excision of the fistulous tracts and associated accessory salivary gland tissue is the standard approach, with generally good outcomes. Careful surgical technique is important to avoid damage to the orbicularis oris muscle and to achieve an acceptable cosmetic result. Genetic counseling may be offered to affected families, as the condition can be inherited. Distinguishing isolated lower lip fistula from Van der Woude syndrome is clinically important, as the latter carries a risk of cleft lip/palate in offspring due to mutations in the IRF6 gene.

Common questions about Isolated lower lip fistula