
A 7-year-old girl presented with pain and discomfort in the left leg that was exacerbated by physical activity. She had been born with a port-wine stain on the left knee. As her mobility increased, she occasionally complained of discomfort in the left leg. Klippel-Trenaunay syndrome (KTS) was diagnosed at age 3 years after an evaluation for swelling, discoloration, and pain of the left leg. Magnetic resonance angiography and venography had revealed abnormally dilated, tortuous veins in the subcutaneous tissues from the distal thigh to the posterolateral calf with involvement of the proximal anterior tibial muscle. The parents had elected for conservative management with observation.