Thyroid Embryonic Anomalies Involving the Medial and Lateral Anlagen: Two Surgical Case Reports.

In all partial or complete thyroidectomy cases, care should be taken to palpate or to use intraoperative ultrasound (IOUS) for any extra thyroid mass. An intuitive surgical approach is needed to evaluate for possible embryologic anomalies of the thyroid. There are two thyroid anlagen that can explain ectopic aberrant anomalies: the median anlage-thyroid rest and the lateral anlage from the ultimobranchial body of the fourth pharyngeal pouch. Surgeons should keep in mind that multiple ectopic thyroid glands could be present in any thyroidectomy procedure.