A large thymic mass - a possible cause of unexpected death

Thymic cysts are particularly rare, and because most are asymptomatic, they are usually found incidentally as unsuspected masses on chest radiographs. We report two cases, one congenital and the other neoplasic thymic cysts, both presented initially as idiopathic thymic cysts, and later in association with chronic respiratory or cardiac symptoms developed in relation with widening of the mediastinal shadow confirmed on chest radiographs. Morphological evidence of hemorrhage into thymic cyst was found in a patient and ischemic necrosis to another. These cases emphasize that enlargement of the nonneoplasic and neoplasic thymic cysts may cause acute or chronic symptoms of airway or cardiac compression with widening of the mediastinum. Thymic cysts should be added to the list of thymic abnormalities that may occur in patients with compressive mediastinal masses, which can be sometimes lifethreating for patient.