Thyroid development and its disorders: genetics and molecular mechanisms.

Stazione Zoologica Anton Dohrn, University of Naples Federico II, 80121 Naples, Italy.
Endocrine Reviews (Impact Factor: 19.36). 11/2004; 25(5):722-46. DOI: 10.1210/er.2003-0028
Source: PubMed

ABSTRACT Thyroid gland organogenesis results in an organ the shape, size, and position of which are largely conserved among adult individuals of the same species, thus suggesting that genetic factors must be involved in controlling these parameters. In humans, the organogenesis of the thyroid gland is often disturbed, leading to a variety of conditions, such as agenesis, ectopy, and hypoplasia, which are collectively called thyroid dysgenesis (TD). The molecular mechanisms leading to TD are largely unknown. Studies in murine models and in a few patients with dysgenesis revealed that mutations in regulatory genes expressed in the developing thyroid are responsible for this condition, thus showing that TD can be a genetic and inheritable disease. These studies open the way to a novel working hypothesis on the molecular and genetic basis of this frequent human condition and render the thyroid an important model in the understanding of molecular mechanisms regulating the size, shape, and position of organs.

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    ABSTRACT: Thyroid carcinoma arising in an extrathyroid area is a rare entity. We report a case of anaplastic carcinoma in the submandibular region occurring in a 70-year-old woman. The location of the mass along with no evidence of primary tumor at the orthotopic thyroid gland posed a diagnostic dilemma: was this an ectopic thyroid carcinoma or rather a case of occult differentiated thyroid carcinoma metastasis that transformed to anaplastic carcinoma? Based on the histopathological findings we concluded that the tumor arised in ectopic thyroid tissue. Although the mass was completely resected, the patient died 10 months after diagnosis due to pulmonary metastases. Conclusively, the possibility of ectopic thyroid tissue, with or without disease, should be considered in cases of a mass in the submandibular region. Copyright © 2015. Published by Elsevier Ltd.
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