RESUMO
Klippel Trenaunay Syndrome (KTS) is an uncommon inherited syndrome identified by venous varicosities and capillary abnormalities. von Willebrand Disease is the most common inherited hemorrhage disturbance in humans, leading to insufficiency in von Willebrand Factor, which is a complex multimeric protein with two functions: it forms a bridge between the platelets and injured vascular areas and it attaches factor VIII and stabilizes it. We present a 13-year-old son with a typical clinical manifestation of KTS, including "port-wine stains" as capillary malformation, venous malformation, and hypertrophy of the left lower extremity, who also suffers from von Willebrand Disease type 3. He has been suffering from these two rare conditions since birth. The occurrence of KTS with von Willebrand Factor deficiency in a patient has so far not been reported, which may propose a mutation in the putative common regulatory gene that caused this uncommon phenotype.