Thyroglossal Duct Cyst: Causes, Symptoms, Treatment, Diagnosis

A thyroglossal duct cyst is a condition where there is development of neck lump or mass from the leftover or persistent tissues and cells present after the formation of the thyroid gland. This happens during the embryonic (developmental) stage. Thyroglossal duct cyst is often diagnosed in children who are preschool-aged or in children who are in their mid-adolescence. Thyroglossal duct cyst commonly appears after an upper respiratory infection after which it increases in size and causes pain and other symptoms which often leads to its diagnosis.

Treatment of thyroglossal duct cyst comprises of antibiotics and surgery.

A thyroglossal duct cyst develops congenitally, i.e. this defect is present from the birth of the child itself. When there is formation of thyroid gland during the embryonic stage, it starts at the floor of the tongue and travels down the neck via a canal known as thyroglossal duct. When the thyroid reaches its final stage in its formation, this duct disappears. In some cases, there are portions of the duct remaining which leave behind pockets or cavities which are known as the thyroglossal duct cysts. There can be accumulation of mucus or fluid in these thyroglossal duct cysts which leads to increase in their size and becoming infected. If the size of the thyroglossal duct cyst is very large, then it can cause problems with swallowing and block the breathing passages of the patient.

The symptoms of the thyroglossal duct cyst are similar to other medical conditions and neck masses. So, it is important to make an accurate diagnosis and treat thyroglossal duct cyst accordingly. The following are the common symptoms seen in a patient with Thyroglossal Duct Cyst:

• Patient suffering from thyroglossal duct cyst would have symptoms of a small, soft round mass in the middle front of his/her neck where the hyoid bone is located. This mass can be felt with fingers.
• Patient suffering from thyroglossal duct cyst would have symptoms of redness, tenderness and swelling in the mass, if it is infected. Otherwise, the mass can remain painless and smooth.
• There can be a small opening in the skin adjacent to the mass where the mucus gets drained from the cyst.
• The patient experiences symptoms of difficulty in breathing or swallowing.
• Thyroglossal duct cyst patient can also have symptoms of pain in the upper abdomen.

Physical examination usually helps in making the diagnosis of thyroglossal duct cyst. When the tongue is extended and when the patient swallows, the neck mass usually moves in an upward direction, as the thyroglossal duct is usually connected at the base of the tongue. Determining whether the thyroglossal duct cyst consists of thyroid tissues is important.

Other than medical history and physical examination, investigations which are undertaken for diagnosis of thyroglossal duct cyst are:

• Blood tests are done to check the thyroid function.
• CT scan and ultrasound of the neck is done where a computer and high-frequency sound waves are used to generate images of tissues, blood vessels and organs to look at the muscle surrounding the mass more clearly. Ultrasound also helps in assessing blood circulation through the different vessels and the function of the internal organs.
• Thyroid scan is a diagnostic procedure done, which uses radioactive iodine or technetium to look for any physical abnormalities in the thyroid gland.
• Fine needle aspiration is a procedure, which removes cells present in the thyroglossal duct cyst for further testing and diagnosis.

The treatment of thyroglossal duct cyst depends on the following factors:

• Patient’s age, medical history and general health.
• The extent of the condition, i.e. the thyroglossal duct cyst is also an important consideration when it comes to its treatment.
• Patient’s tolerance for certain medications and therapies/procedures.
• The prognosis of the condition.

Treatment options for thyroglossal duct cyst include:

• Antibiotics are prescribed to treat the infection present in the thyroglossal duct cyst.
• The cyst and the thyroglossal duct are removed surgically or excised with a procedure known as Sistrunk procedure.
• After the removal of the thyroglossal duct cyst, there is a small chance of its re-growth if there are some portions of the tissues remaining after the surgery. Any infection of the cyst before the surgery makes the removal of the duct and the cyst more difficult and also increases the risk of a re-growth.

If the Thyroglossal Duct Cyst is left untreated, then the following complications can occur:

Infection in the thyroglossal duct cyst occurs when it is not treated on time. Patient has swelling in the soft tissues along with obstruction in the airway and difficulty in swallowing due to the cyst enlargement. Rarely, due to infection, the fluid can be discharged into the pharynx which results in other problems within the neck. Infections can occur prior to the removal of the thyroglossal duct cyst and after its removal. Infections occurring after the thyroglossal duct cyst removal consist of shiny skin, skin reactions, dryness and redness from the sutures and from the bacterial exposure of the skin during the healing stage.

There is formation of thyroglossal fistula when there has been incomplete removal of the thyroglossal duct cyst and after the cyst ruptures it leads to formation of draining sinuses, which are known as thyroglossal fistula. This becomes noticeable when there is swelling and fluid ejection due to bleeding in the neck around the site of the thyroglossal duct cyst removal. Patient can also have problems with swallowing and breathing due to the pressure within the neck.

Rarely, thyroglossal cysts cancer can occur. There is formation of tumor, which commonly develops from the ectopic thyroid tissue present inside the cyst. Treatment of this is done by surgically removing the thyroid gland and the lymph nodes for prevention of spreading of the cancer to other areas of the body.