Mediastinal ectopic thyroid diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration: Report of three cases.

An ectopic thyroid gland results from the abnormal migration of the thyroid in the course of its development. Primary ectopic mediastinal thyroid is very rare and occurs in less than 1% of all goiters that can be surgically excised. Ectopic thyroid tissue has a characteristic sonographic appearance as smooth-bordered, homogeneous, hypoechoic tissue with fine specular echoes. We report 3 cases of mediastinal ectopic thyroid diagnosed by endobronchial ultrasound-guided transbrochial needle aspiration biopsy.