Pericardial cysts are a rare entity, accounting for 6-7 percent of all mediastinal masses. They are frequently congenital relating to a failure of fusion of mesenchymal layers forming the pericardial space. Pericardial cysts are considered rare incidental findings, they are mostly asymptomatic and benign, however life-threatening complications may occur. Here we present a case of a silent pericardial cyst that was discovered by chance while performing transthoracic echocardiography (TTE) for a man who was admitted for myocardial infarction.