Intravascular and diffuse dermal reactive angioendotheliomatosis secondaryto iatrogenic arteriovenous fistulas

Reactive angioendotheliomatosis is a rare benign process that has been main ly described in patients with systemic infections, such as subacute bacteri al endocarditis or tuberculosis, and in association with intravascular depo sition of cryoproteins. Histopathologically, it is characterized by a proli feration of endothelial cells within vascular lumina resulting in the oblit eration of the involved vessels. Another rare variant of reactive angioendo theliomatosis has been described in the lower extremities of patients with severe peripheral vascular atherosclerotic disease. It consists of violaceo us and purpuric plaques histopathologically characterized by diffuse prolif eration of endothelial cells interstitially arranged between collagen bundl es of the reticular dermis. This second variant has been named diffuse derm al reactive angioendotheliomatosis. We report two patients with reactive cu taneous angioendotheliomatosis appearing distally to arteriovenous fistulas used for hemodialysis because of chronic renal failure. The first patient showed intravascular reactive angioendotheliomatosis, while the second one had purpuric plaques that were characterized histopathologically by diffuse dermal angioendotheliomatosis. Both patients showed an arteriovenous "stea l" syndrome with distal ischemia, and it is possible that a local increase of vascular endothelial growth factor, as is the case in hypoxia situations , induces the endothelial proliferation. To the best of our knowledge, cuta neous reactive angioendotheliomatosis has not been previously described in association with arteriovenous shunts.