Case Report: A case of antiphospholipid-antibody-associated reactive angioendotheliomatosis and panniculitis

Introduction: Reactive angioendotheliomatosis (RAE) is a benign vascular disorder with a varied clinical presentation that has been associated with a wide range of systemic illnesses. It is characterized histologically by intravascular and extravascular hyperplasia of endothelial cells and pericytes, and this entity only affects the skin. We present the rare case of a woman with both RAE and panniculitis associated with anticardiolipin antibodies in the setting of antiphospholipid syndrome (APLS). Case description: A female in her forties presented for a second opinion of lumps in her skin. The first lump was noted on her right thigh four years prior to presentation, and biopsy demonstrated longstanding septal and lobular panniculitis. Studies that followed this finding revealed a diagnosis of APLS, and the patient had been placed on 400 mg per day of hydroxychloroquine and a daily low-dose of aspirin. She presented with a new subcutaneous plaque on the left lower back, and biopsy of this lesion was suggestive of RAE. She had no history of significant thrombotic events and had never been treated with an anticoagulant. Work-up was negative for other connective tissue diseases that are known for producing subcutaneous nodular lesions. Discussion: RAE is very rare, with less than 50 cases reported in total; five of these in association with APLS. In the context of APLS, RAE is likely a result of the procoagulant state induced by the presence of antiphospholipid antibodies. This case of both RAE and panniculitis associated with anticardiolipin antibodies in the setting of APLS describes rare manifestations of APLS as isolated incidents in a relatively healthy patient.