Livedo, dementia, thrombocytopenia, and endotheliitis without antiphospholipid antibodies: seronegative antiphospholipid-like syndrome.

We report a 51-year-old woman who presented with dementia, livedo racemosa, polyarthralgia, mild renal insufficiency, proteinuria, and thrombocytopenia. Cutaneous and renal biopsy specimens both showed an identical specific occlusive arteriolopathy consistent with Sneddon syndrome and antiphospholipid syndrome. However, no antiphospholipid antibodies were detected and we, therefore, diagnosed seronegative antiphospholipid-like syndrome. We discuss the nosology of this entity and its association with non-antiphospholipid antibody-related Sneddon syndrome. The common denominator of Sneddon syndrome and antiphospholipid syndrome with or without antiphospholipid antibodies seems to be the endothelial damage and occlusive arteriolopathy. Skin biopsy is useful to confirm the diagnosis of seronegative antiphospholipid-like syndrome.