ectopic thyroid

Thyroglossal
duct pathology and mimics. Ectopic thyroid tissue. Axial contrast-enhanced CT image demonstrates a focal high attenuating soft tissue mass in the midline anterior neck along the anterior margin of the thyroid cartilage (arrow). Invaginated by strap musculature, this mass resembles the thyroid gland in attenuation and occurs in expected course of the thyroglossal duct tract
insightsimaging.springeropen.com • CC-by-4.0
Ectopic
Infrahyoid Thyroid with Coexisting Orthotopic Thyroid Gland. Note the avidly enhancing tissue inferior to the hyoid bone, anterior to the laryngeal prominence of the thyroid cartilage, suggestive of ectopic thyroid tissue (purple arrow).
www.eurorad.org • CC by-nc-sa-4.0
Dual ectopy
thyroid - a case report. Well-defined hyperdense lesion seen in the left sublingual region (due to intrinsic iodine content in thyroid tissue), showing plain computed tomography 123HU (Hounsfield unit).
www.eurorad.org • CC by-nc-sa-4.0
Dual ectopy
thyroid - a case report. Well-defined infra-hyoid, pre-laryngeal neck swelling is hyperdense on plain CT (due to intrinsic Iodine content in thyroid tissue), showing 116HU.
www.eurorad.org • CC by-nc-sa-4.0
Dual ectopy
thyroid - a case report. Three well-defined hyperdense masses at sub-lingual level, anterior to oropharynx and infra-hyoid pre-laryngeal level; showing moderate contrast enhancement.
www.eurorad.org • CC by-nc-sa-4.0
Submandibular
ectopic thyroid gland: an uncommon presentation. Post-contrast-computed tomography image. A Axial view. B Coronal view, showing an enhancing submandibular mass lesion in the left side
ejo.springeropen.com • CC-by-4.0
Laryngo
fiberscopy-guided suspension procedure for an ectopic lingual thyroid obstructing airway. Preoperative imaging tests. Laryngeal endoscopy revealed a lingual mass (arrow head) compressing the epiglottis (arrow) (a). Enhanced CT (b) and thyroid scintigraphy using iodine-123 (c) revealed that the mass (arrow heads) was an ectopic thyroid and that there was no normal pretracheal thyroid gland
surgicalcasereports.springeropen.com • CC-by-4.0
Incidental
lingual thyroid with subclinical hypothyroidism: case report. Head and neck contrast-enhanced axial computed tomographic scan showing a hyperdense soft tissue density in the midline at the base of the tongue (arrow)
ejo.springeropen.com • CC-by-4.0
Incidental
lingual thyroid with subclinical hypothyroidism: case report. Sagittal view of contrast-enhanced CT showing lingual thyroid: a well-defined, rounded, mainly hyper-dense soft tissue density at the base of the tongue (blue arrow); submental abscess (yellow arrow)
ejo.springeropen.com • CC-by-4.0
Thyroglossal
duct pathology and mimics. Lingual thyroid. a Sagittal contrast-enhanced CT image of the neck demonstrates a homogenously enhancing lingual thyroid at the base of the tongue encroaching on the valleculae (arrow). b Axial non-contrast CT shows the inherently high attenuating midline mass at the base of the tongue (arrow). c I-123 thyroid scan confirms the diagnosis, expected iodine uptake of the lingual thyroid (arrow)
insightsimaging.springeropen.com • CC-by-4.0
Ectopic
thyroid tissue in the head and neck: a case series. Distribution of heterotopic thyroid tissue.
bmcresnotes.biomedcentral.com • CC-by-4.0
Ectopic
thyroid tissue in the head and neck: a case series. Axial T2-weighted turbo spin echo unenhanced sequence without fat saturation shows a 4.5 × 4.0 × 3.7-cm hyperintense, rough oval formation suspected to contain mucus.
bmcresnotes.biomedcentral.com • CC-by-4.0
Ectopic
thyroid tissue in the head and neck: a case series. Axial (a) and sagittal (b) unenhanced computed tomography scans show the presence of a hypodense round mass (3 × 4 cm) (arrows) with a fluid density value (mean density = 20 HU) located medially and in front of the hyoid bone (arrowhead).
bmcresnotes.biomedcentral.com • CC-by-4.0
School ager
with stridorLateral 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.The diagnosis was ectopic thyroid.
pediatricimaging.org • CC-by-nc-sa 4.0
Ectopic
Infrahyoid Thyroid with Coexisting Orthotopic Thyroid Gland. Note the well-circumscribed, nodular, homogenously enhancing tissue at the level of the larynx, between the sternohyoid muscles, anterior to the laryngeal prominence, and within the infrahyoid portion of the neck, suggestive of ectopic thyroid tissue.
www.eurorad.org • CC by-nc-sa-4.0
Ectopic
thyroid tissue presenting as a midline neck mass with absent orthotopic thyroid gland. Colour Doppler evaluation of lesion shows internal central and peripheral vascularity.
www.eurorad.org • CC by-nc-sa-4.0
Ectopic
thyroid tissue presenting as a midline neck mass with absent orthotopic thyroid gland. Well-defined heterogeneous lesion with multiple internal cystic areas at suprohyoid neck region in midline.
www.eurorad.org • CC by-nc-sa-4.0
Ectopic
thyroid tissue presenting as a midline neck mass with absent orthotopic thyroid gland. A well-defined heterogeneous lesion with multiple cystic areas is noted in midline suprahyoid region. (Hyoid bone is represented by white star)
www.eurorad.org • CC by-nc-sa-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

An ectopic thyroid gland is one which is located in a location other than the normal position anterior to the laryngeal cartilages.

Terminology

Ectopic tissue refers to the gland located outside its normal anatomical position whereas accessory tissue refers to extra tissue located remote from a normally positioned gland .

Variant anatomy

During embryological development, the thyroid gland migrates down from the foramen cecum at the posterior aspect of the tongue to its permanent location in the infrahyoid neck. This normal migration can be halted at any point, or indeed can go 'off-target' with thyroid tissue coming to rest in unusual locations within the neck or elsewhere :

  • lingual: base of tongue (90%)
  • sublingual: below the tongue
  • prelaryngeal
  • other sites, e.g. mediastinum (<1%), intratracheal

Thyroid tissue may also be present in the normal thyroid bed, so-called "dual ectopic thyroid" .

Radiographic features

As imaging findings (other than location) are identical irrespective of location, the discussion on ectopic thyroids is continued as part of the lingual thyroid article.

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