Ectopic Thyroid

  • Etiology: Migration anomaly as thyroid gland migrates down from foramen cecum at the posterior aspect of the tongue to permanent location in infrahyoid neck
  • Imaging US:
    — Thyroid is absent from its normal position in the neck
    — Lingual thyroid at base of tongue (90%) or sublingual thyroid below the tongue or prelaryngeal thyroid or mediastinal thyroid (less than 1%)
  • Imaging Thyroid scan: Consider nuclear medicine scan to confirm thyroid location
  • Imaging CT: Hyperdense structure on CT with contrast
  • DDX:
  • Complications:
  • Treatment:
  • Clinical:

Radiology Cases of Ectopic Thyroid

Radiograph and nuclear medicine scan of ectopic thyroid
Lateral radiograph of the airway (left) shows a mass at the base of the tongue that when overlaid / registered with a thyroid nuclear medicine scan (right) shows radiotracer uptake in the mass.

Radiology Cases of Ectopic Thyroid in Thyroglossal Duct Cyst

I-123 scan of thyroglossal duct cyst containing thyroid tissue
Anterior view of a I-123 thyroid scan shows tracer uptake in a single midline region that corresponds directly to the patient’s midline neck mass, without any demarcation of the lobes of the thyroid. There was no other thyroid uptake in the neck.

Clinical Cases of Ectopic Thyroid

Clinical Cases of Ectopic Thyroid in Thyroglossal Duct Cyst

Clinical image of thyroglossal duct cyst
AP (above) and lateral (below) clinical images show a large mass in the midline of the neck.

Surgery Cases of Ectopic Thyroid

Surgery Cases of Ectopic Thyroid in Thyroglossal Duct Cyst

Surgery image of thyroglossal duct cyst
Surgical images show the mass (between the forceps) which had been intimately adherent to the mid-point of the hyoid bone and a central tract extending from the mass up to the foramen cecum.

Histopathology Cases of Ectopic Thyroid

Histopathology Cases of Ectopic Thyroid in Thyroglossal Duct Cyst

Histopathology image of thyroglossal duct cyst
Histopathological image H&E stained section shows a fibrous-walled cyst lined by ciliated, respiratory type epithelium (on the left). Scattered, small thyroid follicles (some containing eosinophilic colloid) are noted in the adjacent fibroconnective tissue (on the right).