An approach to mediastinal masses associated with hyperthyroidism.

Benign thymic hyperplasia (BTH) is a known feature of hyperthyroidism, but is infrequently appreciated by clinicians. In most cases thymic enlargement is minimal; however, it may occasionally present as an appreciable anterior mediastinal mass. While surgical resection is a common approach to such a mass, recognition of the benign nature of BTH and its regression following treatment of hyperthyroidism would prevent a major surgical procedure. We present three cases of BTH associated with hyperthyroidism and describe our approach to this syndrome.