It is important to identify whether or not the thyroglossal cyst contains any thyroid tissue, as it can define the degree of cyst that is being dealt with.Diagnostic procedures for a thyroglossal cyst include:

Clinical features
Clinical features can be found in the subhyoid portion of the tract and 75% present as midline swellings. The remainder can be found as far lateral as the lateral tip of the hyoid bone. Typically, the cyst will move upwards on protrusion of the tongue, given its attachment to the embryonic duct, as well as on swallowing, due to attachment of the tract to the foramen caecum. Treatment
Although generally benign, the cyst must be removed if the patient exhibits difficulty in breathing or swallowing, or if the cyst is infected. Even if these symptoms are not present, the cyst may be removed to eliminate the chance of infection or development of a carcinoma,Thyroid scans and thyroid function studies are ordered preoperatively; this is important to demonstrate that normally functioning thyroid tissue is in its usual area.Surgical management options include the Sistrunk procedure, en bloc central neck dissection, suture-guided transhyoid pharyngotomy, and Koempels supra-hyoid technique. Cystectomy is an inadequate approach. Sistrunk Procedure
The Sistrunk procedure is the surgical resection of the central portion of the hyoid bone along with a wide core of tissue from the midline area between the hyoid and foramen cecum.
Differential diagnosis are ectopic thyroid, enlarged lymph nodes, dermoid cysts and goiter.Thyroglossal cyst usually presents as a midline neck lump (in the region of the hyoid bone) that is usually painless, smooth and cystic, though if infected, pain can occur. There may be difficulty breathing, dysphagia (difficulty swallowing), or dyspepsia (discomfort in the upper abdomen), especially if the cyst becomes large.The most common location 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.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. Complications
Infection
An infected thyroglossal duct cyst can occur when it is left untreated for a certain amount of time or simply when a thyroglossal duct cyst hasnt been suspected. The degree of infection can be examined as major rim enhancement has occurred, located inferior to the hyoid bone. Soft tissue swelling occurs, along with airway obstruction and trouble swallowing, due to the rapid enlargement of the cyst. With infections, there can be rare cases where an expression of fluid is projected into the pharynx causing other problems within the neck.