[Pedunculated and Mobile Right Atrial Thrombus Moderately after Mitral Valve Plasty and Tricuspid Valve Annuloplasty:Report of a Case].

An 81-year-old female underwent mitral valve plasty and tricuspid annuloplasty using an artificial annulus for mitral valve insufficiency and secondary tricuspid valve insufficiency at our hospital. Echocardiography 5 months later showed no abnormal finding. Eight months after the operation, however, a pedunculated and highly mobile mass in the right atrium was found, and the patient was admitted to our hospital. Its shape was really uncommon, and it was difficult to differentiate between a thrombus and a tumor. We subsequently performed a surgical removal. The resected mass was filled with many starshaped spherical tissues which were partially organized white thrombi histologically. Damage to the right atrial endocardium during previous surgery could be the cause.