A unique case of a benign disseminated angioproliferation combining features of Kaposi's sarcoma and diffuse dermal angioendotheliomatosis.

A female patient undergoing chronic hemodialysis had disseminated, violaceous, and partly ulcerated plaques develop on the trunk. Lesions had erupted simultaneously over a period of 4 weeks and resolved within 5 months after steroid treatment. By histopathology, the papillary dermis was densely filled with blood vessels lined by a single layer of differentiated endothelial cells, a growth pattern resembling diffuse dermal angioendotheliomatosis. In some areas, endothelial cells were spindle shaped and formed discontinuous lumina. Red blood cells were interspersed within these slits, giving the lesions a kaposiform appearance. By immunohistochemistry, endothelial cells reacted with the antibodies anti-von Willebrand factor, anti-CD31, and anti-CD34 and with the lectin Ulex europaeus-1. The course of the disease combined with the unusual histopathology makes this case a unique form of a benign disseminated kaposiform angioproliferation.