Lipomatous hypertrophy of interatrial septum presenting as recurring pericardial effusion and mistaken for constrictive pericarditis.

A case of interatrial septal lipoma, presenting as recurrent pericardial effusion with signs of constrictive pericarditis, was described. The tumor was removed successfully. The case demonstrated that the difficulties in the differential diagnosis between right atrial tumor and any other cardiac disease still exist. Because of its extreme rarity, the interatrial septal lipoma is rarely considered in the differential diagnosis.