The hallmark of Klippel-Trenaunay syndrome is the presence of cutaneous abnormalities in the limbs or trunk associated with underlying soft tissue hypertrophy. Cutaneous abnormalities include capillary angiomatosis, cavernous hemangiomas, pigmented verrucous lesions, hyperhidrosis, and hypertrichosis. The soft tissue hypertrophy results from vascular abnormalities including varicose veins, phlebectasias, lymphangiomas, and arteriovenous malformations. The neurological manifestations of Klippel-Trenaunay syndrome result from intraspinal and intracranial angiomas. Neurological manifestations are infrequent in the neonatal period. Klippel-Trenaunay syndrome has a sporadic occurrence.

Figure 297.1.— Typical appearance of Klippel-Trenaunay syndrome. Extensive nevus and soft tissue hypertrophy involving the right leg. Lumbosacral hemangioma.