Cardiac hydatid cysts are a rare presentation of hydatid cyst disease in the body, with a reported cardiac involvement rate of <2%. The left ventricle is the most common site of cardiac involvement. Here, we report a patient with a hydatid cyst that ruptured into the pericardium after producing an aneurysm on the right ventricular free wall, appearing as fibrinated fluid and a solid mass lesion in the pericardium. Our aim in this case report was to emphasise that the possibility of a hydatid cyst should not be overlooked in the differential diagnosis of pericardial tumours.
