Malignant angioendotheliomatosis mimicking systemic necrotizing vasculitis.

Malignant angioendotheliomatosis is a rare disease characterized by an intravascular proliferation of atypical mononuclear cells. Manifestations result from occlusion of small blood vessels. Multiple organ systems are involved and the clinical presentation resembles a systemic necrotizing vasculitis with skin and central nervous system most commonly involved. The clinical course is characterized by progressive organ failure with death usually within 2 years after presentation. Based on its assumed origin as an intravascular lymphoma, patients may respond to chemotherapy.