Definition

A rare disorder that affects the blood vessels, soft tissues, and bones. It may also affect the lymph vessels. Klippel-Trenaunay syndrome is marked by a port-wine stain (a red or purplish birthmark caused by swelling of small blood vessels near the surface of the skin), abnormal overgrowth of bone and soft tissue, and varicose veins or other abnormal veins. It usually affects the legs, but it can also affect the arms or trunk. Klippel-Trenaunay syndrome is present at birth.