The thyroid gland is formed at the root of the tongue in embryonic life and moves along the canal called the thyroglossal canal at the 7th week of pregnancy and settles in its normal place in the neck. When the thyroid gland settles in its normal place, this channel, which allows the gland to migrate from the root of the tongue to here, regresses and disappears in the 10th week of pregnancy.

A thyroglossal duct cyst occurs when a part of the duct does not disappear after normal migration and becomes cystic. Thyroglossal duct cyst is the most common congenital neck mass. Although it can be seen at any age, it most commonly occurs between the ages of 2-10.

The thyroglossal duct cyst is almost always located in the middle of the neck, and it is seen that the cyst moves upwards when the tongue is protruded. This is typical for the found thyroglossal cyst.

Diagnosis is made by ear, nose and throat examination and neck ultrasound.

The treatment is surgical removal of these cysts. Cysts that are not surgically removed grow infected. If a thyroglossal cyst becomes infected and opens out, it is called a thyroglossal fistula. Sometimes a tumor may develop from this cyst.