Bilateral blind epithelized tracts associated with the inferior labial frenum.

Examination of a 45-year-old man disclosed, bilateral, blind, epithelium-lined tracts on the alveolar mucosa in proximity to the inferior labial frenum. These structures were excised surgically and examined histologically. This article represents the first report of blind mucosal pits in this location. The mechanism responsible for development of these structures is not clear, but they most likely result from entrapment or persistence of epithelium during embryogenesis.