During fetal development, the thyroid gland starts at the base of the tongue (foramen caecum). From here it gradually travels down the neck to its final position in front of the trachea, beneath the larynx. It leaves a track behind called the thyroglossal duct, which then disappears. When part of the thyroglossal duct persists it can give rise to a fluid filled cyst. This is called a thyroglossal cyst.
Ectopic thyroid tissue is a key differential diagnosis, as this commonly occurs at a similar location.
The main complication is infection of the cyst, causing a hot, tender and painful lump.
Thyroglossal cysts usually occur in the midline of the neck. They are:
Thyroglossal cysts move up and down with movement of the tongue. This is a key feature that demonstrates a midline neck lump is a thyroglossal cyst. This occurs due to the connection between the thyroglossal duct and the base of the tongue.
Ultrasound or CT scan can confirm the diagnosis.
Thyroglossal cysts are usually surgically removed to provide confirmation of the diagnosis on histology and prevent infections.
Sistrunk surgical procedure - The central body of the hyoid bone is removed to allow complete removal of the entire thyroglossal tract. There is a high chance of recurrence if the medial portion of the hyoid bone is not removed.
The cyst can reoccur after surgery unless the full thyroglossal duct is removed.