Thyroglossal Fistula
A thyroglossal duct cyst may rupture unexpectedly, resulting in a draining sinus known as a thyroglossal fistula. Thyroglossal fistula can develop when the removal of the cyst has not been fully completed. This is usually noticed when bleeding in the neck occurs, causing swelling and fluid ejection around the original wound of removal. Thyroglossal duct cyst carcinoma
Rarely (in less than 1% of cases), cancer may be present in a thyroglossal duct cyst. These tumors are generally papillary thyroid carcinomas, arising from the ectopic thyroid tissue within the cyst. Causes
Thyroglossal Duct Cysts are a birth defect. During embryonic development, the thyroid gland is being formed, beginning at the base of the tongue and moving towards the neck canal, known as the thyroglossal duct. Once the thyroid reaches its final position in the neck, the duct normally disappears. In some individuals, portions of the duct remain behind, leaving small pockets, known as cysts. During a persons life, these cyst pockets can fill with fluids and mucus, enlarging when infected, presenting the thyroglossal cyst. Embryology
The thyroglossal tract arises from the foramen cecum at the junction of the anterior two-thirds and posterior one-third of the tongue. Any part of the tract can persist, causing a sinus, fistula or cyst. Most fistulae are acquired following rupture or incision of the infected thyroglossal cyst. A thyroglossal cyst is lined by pseudostratified, ciliated columnar epithelium while a thyroglossal fistula is lined by columnar epithelium. Diagnosis
Diagnosis of a thyroglossal duct cyst requires a medical professional, and is usually done by a physical examination.
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.