The authors present the case of a 55-year-old woman with a nonfunctioning intrapericardial paraganglioma. The tumor was incidentally found during transthoracic echocardiography that was performed because an enlarged cardiac silhouette had been noted on a chest x-ray. Transesophageal echocardiography further elucidated that the left circumflex coronary artery branched and traversed into the intrapericardial mass. Coronary angiography and cardiac multislice computed tomography both confirmed the presence of a vascular intrapericardial mass being fed by the obtuse marginal artery. Moreover, an arterial aneurysmal formation and a coronary arteriovenous fistula were noted within the tumor. After "en bloc" tumor resection, histopathologic and electron microscopic examinations established the diagnosis of a nonfunctioning intrapericardial paraganglioma.