A cyst is a fluid-filled mass that can occur anywhere on or in the body. A thyroglossal duct cyst is located on the front of the throat, in the middle of the neck. This type of neck cyst is not usually found or diagnosed until a few years after a baby is born and after they start to experience symptoms or infection. It may also not be diagnosed until a doctor examines your child’s neck during a routine office visit.
A thyroglossal duct cyst is made of extra cells and tissue from the thyroid gland (a large gland in the neck that produces hormones). During the early stages of development during pregnancy, the baby’s thyroid travels from the base of the tongue through the thyroglossal duct (a tube in the fetus’s neck). Throughout the pregnancy, the baby’s thyroid travels to its proper location at the base of the throat.
After the thyroid has reached the proper position, the thyroglossal duct is no longer needed. It should go away as your baby continues to grow and develop. In cases when the thyroglossal duct does not fully go away, extra cells and tissue remain. Those extra cells and tissues become a small, fluid-filled cyst known as a thyroglossal duct cyst.
A thyroglossal duct cyst is congenital. This means your baby has it from birth. Children with small thyroglossal duct cysts are often asymptomatic (do not experience symptoms). Thyroglossal cysts are usually found when they get infected and swell to a bigger size or get irritated by a separate infection that affects the neck or throat, like an upper respiratory infection (an infection that affects the upper part of the lungs, throat and nose, such as a cold or the flu).
Common symptoms of a thyroglossal duct cyst infection include:
In cases when you can see the cyst, it looks like a round lump or mass on the throat that moves when your child swallows or sticks out their tongue. When it gets infected, it often looks red and swollen and feels tender to the touch. In some cases, mucus may leak from an opening in the skin near the lump. Major swelling may block your child’s airway and cause difficulty breathing or swallowing or uncomfortable pressure at the site of the cyst.