What Is a Thyroglossal Duct Cyst?

A thyroglossal duct cyst is a fluid-filled mass found near the thyroid gland and present at birth in some children. This type of cyst is typically discovered when an infection causes the cyst to become enlarged. Infected cysts can hinder swallowing and may be painful. Ultrasound or thyroid scans are used to verify the presence of a cyst of the thyroglossal duct. Treatment is to remove the cyst or to monitor the size of the cyst.

During gestation, the thyroid gland migrates along the neck by way of a channel called the thyroglossal duct. Following this migration, the duct is reabsorbed by the body. In some children, however, a part of the thyroglossal duct is not completely reabsorbed and is left to form a thyroglossal duct cyst.

Even though this type of cyst is present at birth, it is usually not discovered until an infection causes the thyroglossal duct cyst to swell. The swollen cyst can then be easily palpated by a pediatrician. Enlarged and infected cysts of the thyroglossal duct may also cause a child pain during swallowing, difficulty swallowing, and a sore throat. Occasionally, an infected cyst can be seen bulging out of the neck. Most of the time, this type of cyst is discovered between the ages of two and ten.

Once a thyroglossal duct cyst has been palpated by a pediatrician or is suspected, several tests can be run to confirm the diagnosis. The first test that is typically run is a blood test to determine if the cyst is interfering with the function of the thyroid gland. An ultrasound scan, thyroid scan, or both may also be ordered to visually verify the cyst and determine its size and the relationship of the cyst to the thyroid.

Treatment of a thyroglossal duct cyst depends on the child’s health and age. First, antibiotics will be prescribed to destroy the infection inside the cyst. After the infection has been brought under control or eliminated, the size of the cyst will be reevaluated. If the child can handle surgery and the cyst is large enough to interfere with swallowing and is near the thyroid, a surgical Sistrunk procedure will be performed. If the cyst is fairly small and surgery is not recommended for the child, then the cyst will be periodically reviewed using an ultrasound scan, and thyroid function will be monitored with blood work.

The Sistrunk procedure removes the cyst as well as the tissue along and encompassing the original thyroglossal duct. If some of the thyroglossal duct tissue is left behind, another cyst can form. Sometimes part of the hyoid bone, or the small U-shaped bone located just under the chin, is also removed to be absolutely certain that none of the duct tissue remains in the neck.