Cystic mass formation in constrictive pericarditis and epicarditis after open-heart surgery.

We report a case of locally constrictive pericarditis and epicarditis, which did not indicate typical findings of CT and MRI, late after open-heart surgery. A 74-year-old man with a history of coronary artery bypass grafting was transferred to our hospital for treatment of heart failure. Transthoracic echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI) showed a cystic lesion that compressed the right ventricle and main pulmonary artery without enhancement. However, the pericardial hypertrophy was not clear. We suggested a benign, cystic lesion based on these examinations and planned surgical removal of the mass to release the compression of the heart and to confirm the diagnosis of the capsulized mass. At surgery, cystic mass formation was covered by a thickened fibrous tissue, pericardium and epicardium and was filled with transparent yellowish fluid. We performed a waffle procedure without cardiopulmonary bypass. Histopathologic examination of the excised epicardium revealed neovascularization, minimal inflammation and thickened hyaline connective tissue and was diagnosed as constrictive percarditis and epicarditis.