A congenital vascular disorder characterized byan abnormal connection between an artery and a vein, appearing as varicose veins with port wine discoloration, leading to a bypass of the capillary bed. Signs and symptoms include palpable continuous thrill in the dilated vessels, continuous machinery murmur with systolic accentuation, collapsing arterial pulse, Nicoladoni Branham sign, as well as local gigantism and hot ulcers due to hypoxia, among others.