Coronary artery aneurysms (CAA) are rare but potentially fatal pathologies. This case was referred to our Unit after occasional echocardiographic finding of an intracardiac mass. A new detailed transthoracic echocardiogram was decisive for a diagnosis of a large CAA of the right coronary artery, compressing and dislocating the right atrium. Transesophageal echocardiography was not performed because of the data obtained. The diagnosis was confirmed by cardiac catheterization. The patient was managed with a surgical procedure.