Thyroglossal Duct Cysts
DR C GARWE
THYROGLOSSAL DUCT CYSTS
 Thyroglossal duct cysts arise from a persistent epithelial
tract formed with the descent of the thyroid from the
foramen caecum to its final position in the front of the neck
EPIDEMIOLOGY
 The most common form of congenital cyst in the neck
 Accounts for 2–4% of all neck masses
 Most patients are children or adolescents.
 Up to 1/3 are aged 20 years or older.
 Predominant age: 50% <10 years, 65% <20 years
 Male = Female
 About 7% of the poipulation
 Carcinoma in about 1-2% of patients.
 Fewer than 5% have ectopic thyroid tissue
EMBRYOLOGY
 During the 4th week of gestation, a ventral diverticulum of the foramen
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cecum is formed from the first and second pharyngeal pouches (the
medial thyroid anlage).
This diverticulum, with its narrow neck connected to the tongue,
descends in the midline of the neck as the thyroglossal tract to the
position of the normal thyroid in the base of the neck, where the thyroid
lobes separate, by the seventh week.
The path of descent is usually anterior to the hyoid bone but may be
posterior to or through the bone and ends on the anterior surface of the
first few tracheal rings.
The tract usually atrophies and disappears by the tenth week of
gestation.
Portions of the tract and remnants of thyroid tissue associated with it
may persist at any point between the tongue and the thyroid
LOCATION OF TDC
 Lingual: 2% Suprahyoid: 24% Thyrohyoid: 61% Suprasternal:
13% Mediastinal: Rarely
 may present lateral to midline in 10% - 20%, but never
lateral to large neck vessels
 Mainly deviate to the left, because levator glandulae
thyroideae is ordinarily found to the left
PRESENTATION
 Most often asymptomatic, midline upper neck mass that is
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cystic
Swelling, painless or slightly tender
1/4 of patients present with a draining sinus.
Foul taste in the mouth if the spontaneous drainage occurred
by way of the foramen cecum
Severe respiratory distress from lesions at the base of the
tongue
Infected thyroglossal duct cyst may manifest as tender mass
with associated dysphagia, dysphonia, draining sinus, fever, or
increasing neck mass
PHYSICAL EXAMINATION
• Note cystic mass and movement with deglutition
The mass is not mobile in the lateral plane, but moves in the vertical plane
• Within 2 cm of midline
Of note, 25% are found just lateral to midline, with the majority of these on
the left
• Examine base of tongue for lingual thyroid (90% ectopic
thyroid found at base of tongue)
• Palpate neck for cervical thyroid
DIAGNOSTIC WORKUP
 Clinical
 Ultrasound is the preoperative investigation of choice.
 Ultrasound is readily available, inexpensive, non-invasive,
and does not involve ionizing radiation or sedation.
 A simple TDC will appear as an avascular, anechoic structure
with posterior acoustic enhancement on US.
 CT and MRI play a supplementary role to more accurately
delineate anatomy of large cysts
 MRI may be utilized to define a residual fistulous tract in
recurrent disease
 In adults, CT is the preferred modality for several reasons:
 Thyglossal duct cystis less frequently diagnosed in adulthood,
so the differential is broader
 The radiation risk is lower in adults than in children
 The risk of carcinoma is substantially higher in adults, and
CT can better identify the suggestive features of malignancy
THYROID SCANNING
 Generally necessary but is reserved for patients who have
either no detectable thyroid tissue in the neck on
examination, or who following surgery have thyroid tissue
noted within the surgical specimen.
LABORATORY INVESTIGATIONS
 Thyroid function tests
DIFFERENTIAL DIAGNOSIS
 Ectopic midline thyroid
 Dermoid cyst
 Thyroid adenoma of isthmus or pyramidal lobe
 Lymphadenitis
 Cervical thymic cyst
 Sebaceous (epidermal) cysts
 Medial branchial cleft cyst
 Salivary gland tumor
 Lymphatic malformations
 Lipoma
 Hypertrophic pyramidal lobes of the thyroid
TREATMENT
 Complete removal of the cyst along with the extension to the
base of the tongue.
 This is done in conjunction with removal of the central
portion of the hyoid bone and is known as the Sistrunk
procedure.
 Under general anaesthesia.
SISTRUNK PROCEDURE
COMPLICATIONS OF THE SISTRUNK
PROCEDURE
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Bleeding, infection, reaction to anesthesia, scarring
Damage to adjacent structures: superior laryngeal nerve, hypoglossal
nerve (rare)
Recurrence: 4% for first operations with Sistrunk, higher if portion of
hyoid is not removed
Orocutaneous fistula
Hypothyroidism
Potential swallowing alteration
RECURRENT DISEASE
 Recurrence after complete excision using Sistrunk procedure is
reported to be 2.6–5% (5).
 Increased risk of recurrence:
 Failure to completely excise the cyst
 In children <2 years of age, intraoperative cyst rupture and presence
of a cutaneous component
 Preoperative or concurrent infection of the cyst at the time of the
surgery
 After excision, thyroglossal cyst has a high risk for recurrence
(20–35%) and requires a wider en bloc resection.
 Most cases of thyroglossal duct cyst carcinoma are treated
adequately by Sistrunk procedure, with a reported cure rate of
95%.
TREATMENT OF RECURRENT DISEASE
 An extended or wide local incision is recommended in the
suprahyoid area including tongue base muscles and foramen
cecum mucosa,removal of at least 2/3 of hyoid bone
remnants, and a wide local incision of infrahyoid and the
space posterior to the hyoid bone
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