Angiokeratoma circumscriptum is a benign, relatively uncommon form of cutaneous vascular ectasia. It presents as one or more dark red, maroon, or blue-black papule, plaque, or nodule that may have a keratotic or verrucous surface. It is most often found unilaterally on a lower limb.

Angiokeratoma circumscriptum has been associated with Klippel-Trenaunay-Weber syndrome (osteohypertrophy of a limb), Cobb syndrome, port-wine stain, cavernous hemangiomas, and arteriovenous fistulas. The condition is present at birth or develops by early childhood, with lesions often increasing in size during adolescence. Female patients are affected more commonly than male patients.