Resection of intrapericardial hibernoma associated with constrictive pericarditis.

Hibernoma is a benign soft-tissue tumor, which arises from the remnants of fetal brown adipose tissue. Out of less than 300 cases of hibernoma described to date, pericardial sac is an unusual localization to develop. When the tumor increases in size, this benign pathology can lead to compression of cardiac chambers and cause life-threatening complications in an asymptomatic patient. Here, the authors present the case of a 20-year-old male who underwent an operation for the treatment of constrictive pericarditis, in which an intrapericardial sessile lesion over diaphragmatic surface of pericardial sac was incidentally discovered. The tumor was excised and diagnosed as hibernoma. No recurrence was evident two years after the procedure.