Apparent association between thymic cysts and prior thoracotomy.

Three male subjects, aged 8 months to 18 years, who had previously undergone thoracic surgery, developed mediastinal thymic cysts. Two cysts, both multilocular, were shown by plain radiography and computed tomography, and one was found incidentally during cardiac surgery. These three cysts constitute 15% of the 20 thymic cysts removed surgically or found at autopsy at the authors' hospital in the past 27 years. These cases and three previously reported cases in male adolescents and adults suggest that some thymic cysts are related to trauma during surgery.