Klippel-Trenaunay syndrome in a boy with concomitant ipsilateral overgrowth and undergrowth.

Klippel-Trenaunay syndrome comprises congenital vascular malformations of the capillary (nevus flammeus), venous (varicosities) or lymphatic systems and disturbed (usually over-) growth of one or more extremities and adjacent parts of the trunk. In some individuals the affected body area may show reduced rather than increased growth. Such patients have been described inverse Klippel-Trenaunay syndrome and included within the spectrum of the syndrome. We report on a 3-year-old boy with vascular malformation of the nevus flammeus type extending from the right buttock to the sole of the right foot with clinical and radiological evidence of leg varicosities and underlying deficiency of the soft tissues and bone. In addition, he had macrodactyly of the first, second, and third toes with small nails, and cutaneous syndactyly of the second and third toes of the ipsilateral foot. Cranial magnetic resonance imaging showed high signal lesions in the peritrigonal areas with normal spinal images. This mosaic phenotype demonstrates that decreased and increased growth can coexist in the same body area of an individual with Klippel-Trenaunay syndrome.