[Non-bacterial thrombotic endocarditis on the bicuspid aortic valve in a 25-year-old male with lupus anticoagulant].

Non-bacterial thrombotic endocarditis (NBTE) is characterized by presence of sterile vegetations that develop from fibrin and platelets on heart valves. The main conditions predisposing to NBTE are malignancy, autoimmune diseases and other hypercoagulable states. The authors describe a case of a 25-year-old male, in whom NBTE was diagnosed on the bicuspid aortic valve. The presence of significant aortic regurgitation and dental caries were initially suggestive of infective endocarditis; although, serial blood culture were negative and procalcytonin concentration was within normal ranges. Empiric antibiotic therapy did not result in diminishing of vegetations, similarly to the anticoagulation treatment initiated when strongly positive lupus anticoagulant was detected in laboratory findings. Aortic valve replacement was necessary. Bacteriologic examination of the excised valve was negative. Widespread fibrin masses at different stages of organization on the leaflets confirmed NBTE in histopathologic assessment. Lupus anticoagulant was probably secondary to thyroid autoimmune disease.