Leg ulcers in the primary antiphospholipid syndrome. Report of a case with a peculiar proliferative small vessel vasculopathy.

Leg ulcers are associated with antiphospholipid antibodies in patients with systemic lupus erythematosus. They may also occur in patients with primary antiphospholipid syndrome(PAPS). Histopathologic findings at the edges of the ulcers may give insight into their pathogenesis. In a patient with PAPS and a leg ulcer, a biopsy of the ulcer's edge revealed a peculiar small vessel nodular proliferation in the upper and lower dermis. There was mild mixed inflammatory infiltrate in the surrounding connective tissue, a few vessels with fibrin thrombi, and some with fibrin deposition within their walls. A review of the literature revealed similar findings in other skin ulcers associated with lupus anticoagulants. This suggests peculiar pathogenetic mechanisms that may be akin to those responsible for antiphospholipid arterial vasculopathy.