Thyroglossal cyst
Encyclopedia
A thyroglossal cyst is a fibrous cyst that forms from a persistent thyroglossal duct
.
) that is usually painless, smooth and cystic, if infected pain can occur. There may be difficulty breathing, dysphagia
(difficulty swallowing), and/or dyspepsia
(discomfort in the upper abdomen), 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.
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
.
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.
The persistent duct or sinus can promote oral secretions, which may cause cysts to become infected. Up to half 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 sometimes cause the transient appearance of a mass or enlargement of the cyst, at times with periodic recurrences. Spontaneous drainage may also occur.
Typically, the cyst will move upwards on protrusion of the tongue, given its attachment to the embryonic duct.
, often requiring concomitant removal of the midsection of the hyoid bone
(Sistrunk procedure), to prevent recurrence. Although generally benign the cyst will 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, or for cosmetic reasons if there is unsightly protrusion from the neck.
The Sistrunk procedure involves excision not only of the cyst but also of the path's tract and branches. A removal of the central portion of the hyoid bone is indicated to ensure complete removal of the tract. It is unlikely that there will be a recurrence after such an operation. The original Sistrunk paper is available on-line with a modern commentary. At times antibiotics can be indicated if there is sign of infection.
Thyroid scans and thyroid function studies are ordered preoperatively; this is important to demonstrate that normally functioning thyroid tissue is in its usual area.
Persistent thyroglossal duct
A persistent thyroglossal duct is a usually benign medical condition in which the thyroglossal duct, a structure usually only found during embryonic development, fails to atrophy...
.
Presentation
It usually presents as a midline neck lump (in the region of the hyoid boneHyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
) that is usually painless, smooth and cystic, if infected pain can occur. There may be difficulty breathing, dysphagia
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
(difficulty swallowing), and/or dyspepsia
Dyspepsia
Dyspepsia , also known as upset stomach or indigestion, refers to a condition of impaired digestion. It is a medical condition characterized by chronic or recurrent pain in the upper abdomen, upper abdominal fullness and feeling full earlier than expected when eating...
(discomfort in the upper abdomen), 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
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
or just above the hyoid bone. A thyroglossal cyst can develop anywhere along a thyroglossal duct
Thyroglossal duct
The thyroglossal duct is an embryological anatomical structure forming an open connection between the initial area of development of the thyroid gland and its final position....
, 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
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
.
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
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
.
Embryology
The thyroglossal tract arises from the foramen cecumForamen cecum (tongue)
The dorsum of the tongue is convex and marked by a median sulcus, which divides it into symmetrical halves; this sulcus ends behind, about 2.5 cm from the root of the organ, in a depression, the foramen cecum , from which a shallow groove, the sulcus terminalis, runs lateral and anterior on either...
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.
Symptoms
Thyroglossal duct cysts most often present with a palpable (able to be felt) asymptomatic midline neck mass below the level of the hyoid bone. The mass on the neck moves during swallowing or on protrusion of the tongue because of its attachment to the tongue via the tract of thyroid descent. Some patients will have neck or throat pain, or dysphagia.The persistent duct or sinus can promote oral secretions, which may cause cysts to become infected. Up to half 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 sometimes cause the transient appearance of a mass or enlargement of the cyst, at times with periodic recurrences. Spontaneous drainage may also occur.
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.Typically, the cyst will move upwards on protrusion of the tongue, given its attachment to the embryonic duct.
Treatment
Treatment for a thyroglossal cyst is surgical resectionSegmental resection
Segmental resection is a surgical procedure to remove part of an organ or gland. It may also be used to remove a tumor and normal tissue around it. In lung cancer surgery, segmental resection refers to removing a section of a lobe of the lung.- External links :* entry in the public domain NCI...
, often requiring concomitant removal of the midsection of the hyoid bone
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
(Sistrunk procedure), to prevent recurrence. Although generally benign the cyst will 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, or for cosmetic reasons if there is unsightly protrusion from the neck.
The Sistrunk procedure involves excision not only of the cyst but also of the path's tract and branches. A removal of the central portion of the hyoid bone is indicated to ensure complete removal of the tract. It is unlikely that there will be a recurrence after such an operation. The original Sistrunk paper is available on-line with a modern commentary. At times antibiotics can be indicated if there is sign of infection.
Thyroid scans and thyroid function studies are ordered preoperatively; this is important to demonstrate that normally functioning thyroid tissue is in its usual area.
See also
- Cutaneous columnar cystCutaneous columnar cystCutaneous columnar cysts are a cutaneous condition, a group of different cysts lined by columnar epithelium. Types of cysts included in this group are:* Bronchogenic cyst* Branchial cyst* Thyroglossal duct cyst* Cutaneous ciliated cyst* Median raphe cyst...
- Branchial cleft cystBranchial cleft cystA branchial cleft cyst is an oval, moderately movable cystic mass that develops under the skin in the neck between the sternocleidomastoid muscle and the pharynx.-Pathology:...
- Cystic hygromaCystic hygromaA cystic hygroma is a congenital multiloculated lymphatic lesion that can arise anywhere, but is classically found in the left posterior triangle of the neck. This is the most common form of lymphangioma. It contains large cyst like cavities containing watery fluid.Microscopically cystic hygroma...
- Preauricular sinus and cystPreauricular sinus and cystA preauricular sinus or cyst A preauricular sinus or cyst A preauricular sinus or cyst (also known as a "Congenital auricular fistula," "Congenital preauricular fistula," "Ear pit", and "Preauricular cyst"...
- RanulaRanulaMucocele is the most common lesion of the salivary glands. Mucoceles are the result of trauma. It results from either blockage or rupture of a salivary gland duct, with consequent leakage of saliva into the surrounding connective tissue stroma. Clinically, they present as a fluctuant swelling of...