Thyroglossal cyst

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**Thyroglossal cyst**
*Classification & external resources*
ICD-10	Q 89.2
ICD-9	759.2
OMIM	188455
DiseasesDB	13070
eMedicine	ent/283

A thyroglossal cyst is a fibrous cyst that forms from a persistent thyroglossal duct. It usually presents as a painful midline neck lump when it becomes infected. There may be dyspepsia or dysphagia and/or difficulty 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.

Very rarely, the persistent duct can become cancerous, called thyroglossal duct carcinoma. In the case of thyroglossal duct carcinoma, the cancerous cells are ectopic thyroid tissue that has been deposited along the thyroglossal duct and usually follows exposure to radiation.

1 Embryology
2 Symptoms of Thyroglossal Duct Cyst
3 Clinical features
4 Treatment
5 Bibliography

[edit] Embryology

The thyroglossal tract arises from foramen caecum at junction of anterior 2/3 and posterior 1/3 of the tongue, any part of the tract can persist causing a sinus, fistulae or cyst. Most fistulae are found acquired following rupture or incision of the infected thyroglossal cyst.

[edit] Symptoms of Thyroglossal Duct Cyst

Thyroglossal duct cysts are most often present with a paplpable (able to be felt) asymptomatic midline neck mass or below the level of the hyoid bone. The mass on the neck moves during swallowing. Some patients will have neck or throat pain, or dsphagia (difficulty swallowing).

Since the persistent duct or sinus can promote oral secretions, such as cysts can become infected. Up to 1/2 of thyroglossal cysts are not diagnosed until adult life. The tract can lie dormant for years or even decades until some kind of stimulus leads to cystic dilation. Infection can sometime cause transient appearance of a mass or enlargement of the cyst, at times with periodic recurrences. Spontaneous drainage may also accur.

[edit] 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 lateral tip of the hyoid bone. If ingected, aspirate cyst rather than incise, this will allow prevention of a formation of thyroglossal fistular. Male:Felmale ratio is found to be approximately equal: 40% present < 10 years of age, 65% < 35 years of age.