Mediastinal cysts and intrathoracic thyroid tumors.

Benign cysts of the mediastinum are thought to be predominantly congenital in origin. Hence, a thorough understanding of their clinicopathologic characteristics is facilitated by knowledge of the embryologic development of the intrathoracic organs, as outlined in this review. Pertinent radiological and pathologic features of these lesions are also discussed. In addition, ectopic thyroid tissue may give rise to mediastinal masses. The salient attributes of these tumors are considered as well.