Unusual case of nonbacterial thrombotic endocarditis attributable to primary antiphospholipid syndrome.

A 54-year-old man was referred for cardiac evaluation before renal transplantation because of chronic renal failure. His medical history was remarkable for diabetes mellitus, hypertension, and 3 episodes of transient ischemic attack (the most recent was 3 years earlier). A transthoracic echocardiogram showed a large, mobile mass on the anterior leaflet of the mitral valve, with trivial mitral regurgitation (Figure 1; Movie I in the online-only Data Supplement). The mass was originally believed to be a fibroelastoma; endocarditis was not considered initially because of the absence of systemic symptoms. Transesophageal echocardiography showed a 1 2-cm mobile, echodense region on the A2 segment of the mitral valve leaflet (Figure 2 and Movie II in the online-only Data Supplement are 2-dimensional images; Figure 3 and Movie III in the online-only Data Supplement are 3-dimensional images). The patient underwent open cardiac surgery for removal of the mass (Figure 4). Histological examination showed nonbacterial thrombotic endocarditis (NBTE). The patient was discharged from the hospital to his home with long-term anticoagulation therapy. To establish the cause of NBTE, he underwent computed tomography of the chest, abdomen, and pelvis, but no obvious underlying malignancy was identified; however, a seroimmunologic blood test was positive for lupus anticoagulant not associated with connective tissue disease. Therefore, the diagnosis of primary antiphospholipid syndrome was made. In retrospect, this likely was the cause of his transient ischemic attacks.