Fact-sheet: Thyroglossal duct cyst


Updated on 08/26/2020 at 2:19 PM

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Definition

Failure of involution of part of the thyroglossal duct (or Bochdalek's canal = embryonic migration pathway of the thyroid).
This defect may result in a simple cyst or in persistent patency of the entire tract.

It is the most common cervical cystic malformation in children.

Locations:
This is a midline/paramedian lesion.
It lies along the course from the tongue base to the thyroid isthmus.
Its position is most often infrahyoid but may be suprahyoid or at the level of the hyoid bone

Clinical features

  • Cervical mass above the thyroid, painful or painless
  • Midline or paramedian.
  • Fluctuant.
  • Mobile on swallowing, on palpation (transverse mobility > vertical mobility), and on tongue protrusion

Ultrasound

  • Midline formation, anechoic,
    echogenic in case of associated infection or hemorrhage.
  • It is fixed to the deep plane

Objectives:

  • Define the relationship with the hyoid bone
  • Confirm the presence of a normally positioned thyroid gland and the absence of ectopic thyroid tissue.
  • Look for complications: Infection (pain, thickened walls, loss of purely fluid content, perilesional tissue infiltration, lymphadenopathy)

CT

Well-defined hypodense lesion with thin wall enhancement after injection.

MRI

  • Cystic lesion
    (T1 hypointense, T2 hyperintense).

Management

  • Surgery if symptomatic.
    Risk of recurrence if incomplete resection
    (excision of the cyst, the body of the hyoid bone, and ligation of the tract as close as possible to the base of the tongue)

Differential diagnosis

  • Branchial cleft cysts
  • Ectopic thyroid
  • Dermoid or epidermoid cyst
  • Lymphatic malformation