a condition in which someone is born with blood or lymph vessels that do not develop correctly, causing dark spots on the skin and problems with growth and with the veins

Dark stains on the skin are often the only visible sign of Klippel-Trenaunay syndrome on the newborn. 新生儿皮肤上的黑斑往往是先天性血管畸形—骨肥大综合症的唯一表征。