Malignant atrophic papulosis (MAP) was originally described as a variant of thromboangiitis obliterans, but was quickly recognized to be a distinct disease entity. MAP is characterized by narrowing and eventual occlusion of the lumen of small-caliber blood vessels by intimal proliferation and thrombosis. Ultimately, ischemia and infarction of the affected organ or organ system can occur. There are two distinct forms: (1) malignant, which can affect the heart, lungs, eyes, kidneys, pericardium, central nervous system, peripheral nervous system, and gastrointestinal system; and (2) benign, which is limited to the skin. Malignant atrophic papulosis is also known as Degos syndrome.

The incidence of MAP is rare. Only about 200 cases have been reported worldwide since its initial description in 1941. Malignant atrophic papulosis is found among both sexes, predominantly in young adults and in Caucasians of Europe and North America, although cases have been documented in Japan, India, and continental Africa.

The etiology of MAP remains unknown. There have been suggestions of autoimmune, hypersensitivity, viral, and genetic bases for this disease, but to date none have been confirmed. It is also theorized that MAP is not a single entity, but the product of several disease processes.