Klippel-Trenaunay-Weber (KTW) syndrome is a condition marked by a trio of symptoms: uneven limb growth, hemangiomas, and nevi. "Asymmetric limb hypertrophy" involves the enlargement of one limb—typically a leg, three times more likely than an arm—without a corresponding increase in size of the opposite limb. This enlargement affects both the bone and soft tissue. Hemangiomas, which are clusters of blood vessels that grow excessively, can vary greatly in size from small, harmless marks to large, cavernous growths. Nevi are pigmented moles on the skin, and in KTW, they are often accompanied by dark linear streaks caused by excess pigmentation. Although other abnormalities may occur, the triad of symptoms is the hallmark of the syndrome. Most individuals with KTW have an enlarged leg and manage well without extensive treatment, sometimes using only an elastic stocking. However, skin ulcers and other issues can develop on the swollen limb. Typically, the approach to treatment is conservative, and surgery is seldom required. Exceptions include very rare cases where the limb becomes excessively large or when clotting issues arise due to the trapping and destruction of blood platelets in a massive hemangioma, which might necessitate intervention. The cause of KTW syndrome remains unknown.
