Klippel–Trénaunay syndrome formerly Klippel–Trénaunay–Weber syndrome and sometimes angioosteohypertrophy syndrome and hemangiectatic hypertrophy,is a rare congenitalmedical condition in which blood vessels and/or lymph vessels fail to form properly. The three main features are nevus flammeus (port-wine stain), venous and lymphatic malformations, and soft-tissue hypertrophy of the affected limb. It is similar to, though distinctly separate from, the less common Parkes-Weber syndrome