A Thyroglossal Cyst is a remnant of the thyroglossal tract which connects our tongue to the thyroid gland. During its formation, the thyroid gland bud migrates from the base of our tongue (foramen caecum) to our lower neck. It travels along the thyroglossal tract. The Thyroglossal cyst forms due to the persistent remnant of the thyroglossal tract. Usually the tract disappears completely after the thyroid gland is formed. The tract is closely related to the hyoid bone (a semi-circular bone located just above the thyroid cartilage).
Thyroglossal cysts usually present as a swelling at the middle part of the neck above the thyroid cartilage (adam's apple). However, it can also be located anywhere from the base of the tongue up to just above the sternum (chest bone). It is usually painless but sometimes can get infected. When it gets infected, it might be inflammed & painful. Occasionally the infected thyroglossal cyst might rupture and form a thyroglossal sinus.
It is important to confirm that the swelling is not a lingual thyroid gland prior to surgery. This can be done with an ultrasound scan or a thyroid radioisotope scan.
The treatment for thyroglossal cyst is surgery. This surgery is called Sistrunk's surgery. It involves making a small incision on the cyst and removing it completely together with the remnant tract and also part of the hyoid bone. It is not a major surgery but as always all surgery will carry some risks.
Infected thyroglossal cysts should not be operated on. It should be treated with antibiotics first and planned for a surgery later when the infection subsides.
There is a small risk of malignancy (papillary carcinoma) with the thyroglossal cyst although it is very rare.
Differential diagnosis for a thyroglossal cyst include dermoid cyst, sebaceous cyst, lipoma, lingual thyroid gland and lymph nodes.
