Persistent thyroglossal duct

Overview
A persistent thyroglossal duct is a usually benign medical condition in which the thyroglossal duct, a structure usually only found during embryonic development, fails to atrophy. The duct persists as a midline structure connecting the back of the tongue to the thyroid gland.

Background
Early during embryonic development, the thyroglossal duct is a midline structure that connects the back of the tongue to the thyroid gland. The duct usually disappears, or atrophies, during the ninth week of gestation so that in most individuals the thyroid does not connect to the tongue. In individuals with a persistent thyroglossal duct, the duct fails to atrophy, and the connection between the thyroid gland and the tongue is maintained.

Complications
A persistent thyroglossal duct may become fluid filled, forming a thyroglossal duct cyst, the most common type of congenital neck malformation. Such cysts account for approximately 2-4% of all neck masses.