[A case of mitral regurgitation with a giant thrombus thought to be caused by anti-phospholipid syndrome].

A 58-year-old woman suffered from mitral valve regurgitation with a giant thrombus in right atrium was thought to be complicated by anti-phospholipid syndrome (APS). Positive anti-loops anti-coagulant and histories of cerebral infarction and miscarriage strongly indicated the diagnosis of APS. She underwent mitral valve replacement using bileaflet mechanical prosthetic value and removal of thrombus. She recovered uneventfully and strict anti-coagulation therapy has been continuing.