Mitral valve replacement due to Libman-Sacks endocarditis: lower limb cellulitis as a red herring.

A 56-year-old woman was admitted due to new ulceration and acute digital ischaemia on a background of chronic leg ulcers bilaterally. Vasculitis screening returned strongly positive lupus anticoagulant levels and elevated anticardiolipin antibodies; these remained elevated at repeat testing. A diagnosis of antiphospholipid syndrome was made. Transthoracic echocardiogram identified a mitral valve lesion suggestive of vegetation and mild mitral valve regurgitation. Blood cultures taken throughout her inpatient admission were negative. Mechanical mitral valve replacement was performed 3 months later, and subsequent culture of the excised tissue returned as sterile. Histological examination showed no morphological signs of infective endocarditis.