Angioendotheliomatosis in a woman with rheumatoid arthritis.

Reactive angioendotheliomatosis (RA) is a rare self-limited skin condition characterized histopathologically by a proliferation of endothelial cells within vascular lumina, usually as a result of different stimuli such as systemic infections, cryoproteinemias, monoclonal gammopathies, allergic conditions, severe peripheral vascular atherosclerotic disease, and iatrogenic arteriovenous fistulas. We report on a 67-year-old woman with a 20-year history of seropositive rheumatoid arthritis who presented with violaceous swelling of her left forearm. A skin biopsy revealed the histopathologic finding of RA with focal glomeruloid features and deposition of periodic acid-Schiff-positive material. In this systemic disorder, cutaneous manifestations may occur secondary to an immune complex-mediated vasculitic mechanism.