A fibrous cyst that forms from a persistent thyroglossal duct. It presents as a painful midline neck lump when it becomes infected. There may be dyspepsia/dysphagia and/or trouble with breathing, especially if the lump becomes large.

The most common locations for a thyroglossal cyst is midline (or slightly off midline), between the isthmus of the thyroid and the hyoid bone or just above the hyoid bone. A thyroglossal cyst can develop anywhere along a thyroglossal duct, though cysts within the tongue or in the floor of the mouth are rare.

Women are affected more commonly than men.

A thyroglossal cyst will move upwards with protrusion of the tongue.

Thyroglossal cysts are associated with an increased incidence of ectopic thyroid tissue. Occasionally, a lingual thyroid can be seen as a flattened strawberry-like lump at the base of the tongue.

Treatment for an infected thyroglossal cyst is surgical resection, often requiring concomitant removal of the midsection of the hyoid bone.