A thyroglossal cyst is a fluid-filled lump in the midline of the neck formed from a leftover tract from the development of the thyroid gland. The main complication is infection, which causes a hot, tender, painful lump.
Ectopic thyroid tissue is a rare but important differential diagnosis that can cause a lump in a similar location.
Pathophysiology
During fetal development, the thyroid gland starts at the base of the tongue. It gradually travels down the neck to the final position in front of the trachea, beneath the larynx. It leaves behind a tract called the thyroglossal duct, which later disappears. When part of the thyroglossal duct persists, it can give rise to a fluid-filled cyst.
Features
Thyroglossal cysts occur in the midline or close to the midline of the neck. They are:
- Mobile
- Non-tender
- Soft
- Fluctuant
Thyroglossal cysts move up and down with the movement of the tongue, due to the connection between the thyroglossal duct and the base of the tongue.
TOM TIP: A key feature to remember of thyroglossal cysts is movement with the tongue. In an OSCE exam, ask a child with a midline neck lump to stick their tongue out and look for the lump moving upwards.
Management
Ultrasound is usually the initial investigation to confirm the diagnosis.
Surgical removal is the definitive treatment to confirm the diagnosis histologically and prevent infection. The standard operation is the Sistrunk procedure. The cyst can recur after surgery unless the entire thyroglossal duct is removed.
Last updated June 2026
Now, head over to members.zerotofinals.com and test your knowledge of this content. Testing yourself helps identify what you missed and strengthens your understanding and retention.
