Ectopic thyroid gland: description of a case and review of the literature.

The clinical occurrence of ectopic thyroid gland is an infrequently encountered condition, resulting from a developmental abnormality during the migration of the thyroid anlage from the floor of the primitive foregut to its final position in the neck. It can be found along the way of thyroid descent, in the midline, or laterally in the neck or even in the mediastinum or under the diaphragm. This condition is often asymptomatic, whereas symptoms could be related to ectopic thyroid size, to its relationships with surrounding organs or to diseases affecting the ectopic thyroid in the same way they involve orthotopic glands. Sometimes, a growing mass can lead to the clinical suspicion of a tumor disease. On the other hand, thyroid ectopy must be distinguished from metastasis of thyroid cancer. Scintigraphy and ultrasonography are the main diagnostic means for evaluating ectopic thyroid tissue, whereas fine needle aspiration could be useful in the presence of a nodular ectopic gland or when the coexistence of an orthotopic thyroid can arise the suspicion of a metastasis from a thyroid cancer. Surgical removal is indicated in symptomatic cases, whereas radioiodine ablation is reserved to recurrent disease. In this paper we report an emblematic case of ectopic thyroid gland and a review of the literature dealing with this condition.