Chronic expanding hematoma in the pericardial cavity after cardiac surgery.

We report the successful surgical treatment of a rare case of chronic expanding hematoma in the pericardial cavity that developed into a very large mass over a long period. The patient, who had a history of cardiac surgery for a double-outlet right ventricle 14 years previously and for tricuspid regurgitation 8 years ago, noticed a slowly growing mass near the left atrium and ventricle 5 years ago. The mass, which confirmed a diagnosis of chronic expanding hematoma, was resected by left thoracotomy.