Thyroid gland and surgery of the thyroglossal duct: exercise in applied embryology.

Thyroglossal duct cysts (TDCs), the most common congenital cervical abnormality, originates from the medial anlage of the thyroid gland and presents as a painless asymptomatic midline suprahyoid mass. It does not represent a diagnostic challenge. The tract may persist as a fibrous cord or leave nests of cells anywhere along its embryonic path, and it gives rise to the development of TDC. The Sistrunk operation described in 1920 consists of en bloc cystectomy and central hyoidectomy, with tract excision up to the foramen cecum. This procedure remains an effective treatment for TDC. Malignant degeneration of TDC is rare (0.7%).