Thyroid dysgenesis

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Thyroid dysgenesis
Other namesThyroid agenesis
CT scan and scintigraphy images of lingular ectopic thyroid
SpecialtyEndocrinology

Thyroid dysgenesis is a cause of congenital hypothyroidism[1] where the thyroid is missing, ectopic, or severely underdeveloped. It should not be confused with iodine deficiency, or with other forms of congenital hypothyroidism, such as thyroid dyshormonogenesis, where the thyroid is present but not functioning correctly.

Congenital hypothyroidism caused by thyroid dysgenesis can be associated with PAX8.[2]

Ectopic thyroid

An ectopic thyroid, also called accessory thyroid gland, is a form of thyroid dysgenesis in which an entire or parts of the thyroid located in another part of the body than what is the usual case. A completely ectopic thyroid gland may be located anywhere along the path of the descent of the thyroid during

foramen cecum of the tongue. In this location, an aberrant or ectopic thyroid gland is known as a lingual thyroid.[3] If the thyroid fails to descend to even higher degree, then the resulting final resting point of the thyroid gland may be high in the neck, such as just below the hyoid bone.[3] Parts of ectopic thyroid tissue ("accessory thyroid tissue") can also occur, and arises from remnants of the thyroglossal duct, and may appear anywhere along its original length.[3] Accessory thyroid tissue may be functional, but is generally insufficient for normal function if the main thyroid gland is entirely removed.[3]

Lingual thyroid is 4-7 times more common in females, with symptoms developing during puberty, pregnancy or menopause. Lingual thyroid may be asymptomatic, or give symptoms such as

dyspnea (difficulty breathing).[4]

References

  1. PMID 12165566
    .
  2. S2CID 33957230
    .
  3. ^ a b c d emedicine > Embryology of the Thyroid and Parathyroids > Thyroid Embryology Clinical Correlations By David J Kay and Arlen D Meyers. Updated: Jan 14, 2010
  4. ISBN 978-0721690032.{{cite book}}: CS1 maint: multiple names: authors list (link
    )

External links

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