Failure of descent of thyroid analage can be seen in the tongue
**Core Concept**
The failure of descent of the thyroid anlage is a critical developmental anomaly that affects the formation of the thyroid gland and other structures in the neck region. This process involves the proper migration and development of the thyroid primordium from its origin in the pharyngeal floor to its final position in the neck.
**Why the Correct Answer is Right**
The failure of descent of the thyroid anlage can result in ectopic thyroid tissue formation, which is often found in the tongue, specifically in the base of the foramen cecum. This occurs due to the incomplete migration of the thyroid primordium during embryonic development. The presence of ectopic thyroid tissue in the tongue can be detected through histopathological examination and is often associated with thyroid dysgenesis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the failure of descent of the thyroid anlage is not typically associated with the formation of ectopic thyroid tissue in the larynx.
**Option B:** This option is incorrect as the failure of descent of the thyroid anlage is not typically associated with the formation of ectopic thyroid tissue in the mediastinum.
**Option C:** This option is incorrect as the failure of descent of the thyroid anlage is not typically associated with the formation of ectopic thyroid tissue in the anterior abdominal wall.
**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that ectopic thyroid tissue in the tongue can be a cause of thyroid nodules and goiter, especially in patients with a history of thyroid dysgenesis or other thyroid developmental anomalies.
**Correct Answer:** D.