Thyroglossal duct cysts (TGDC) are the most common type of congenital neck cysts and pediatric neck masses (90% before the age of 10 years). Typically seen as a painless rounded midline anterior neck swelling or if infected, as a red warm painful lump.

The cysts can occur anywhere along the course of the thyroglossal duct from the foramen cecum to the thyroid gland although infrahyoid location is most common.

They can be diagnosed with multiple imaging modalities including ultrasound, CT and MRI.

Associated ectopic thyroid in ~40% of cases.