K-T syndrome is also known as Klippel-Trenaunay-Weber syndrome, Parkes-Weber syndrome, ollier-Klippel-Trenaunay syndrome, Weber (FP) syndrome, hypertrophic vasodilatation, osteohypertrophic nevus, nevus-varicose vein bone hypertrophy, osteohypertrophic varicose vein nevus syndrome, vascular -hypertrophic bone syndrome, hyperplastic vasodilatation, cutaneous spinal cord hemangioma. The syndrome was first described by Klippel and Trenaunay in 1900, and a similar case was reported by Parker Weber in 1907. The syndrome is characterized by vascular nevi, varicose veins, limited hypertrophy of the soft tissues and bones of the affected limbs, and ocular abnormalities, and is now known as vascular-osteopathic hypertrophy syndrome. Pathogenesis The etiology is unknown. It is irregularly dominant with different phenotypes and recessive in consanguineous marriages. It may be associated with hereditary weakening of the interstitial tissue of the vascular wall and is considered to be a hemangioma with vascular malformations. There are also various opinions on its pathogenesis such as vascular theory, neurological theory and embryonic developmental anomalies theory. Clinical manifestations Klippel-Trenaunay suggested that there are three main symptoms in this syndrome: 1. Segmental distribution of vascular nevi throughout the lower limbs. 2. 2. Early varicose veins that appear from birth or infancy and are limited to the affected side. 3. Hypertrophy of all damaged tissues on the affected side, especially bone tissue, which increases in size, length, width and thickness. Mullins summarized the following manifestations: 1, vascular anomalies: bright red nevus; congenital arteriovenous aneurysm; capillary hemangioma; cavernous hemangioma; congenital varicose veins; lymphangioma; any combination of the above. 2. Trophic changes of soft tissues and bones: hypertrophy or atrophy of soft tissues; hypertrophy or atrophy of bone tissues; 3. Comorbidities: edema; phlebitis; embolism; compensatory curvature of the spine or damage to the hip joint caused by excessive length or shortness of the affected limb; dysfunction of the affected area; stasis dermatitis; ulcers; various types of decalcification of the damaged bone; excessive sweating in the damaged area; hypertension; sensory abnormalities. Ocular manifestations include unilateral congenital glaucoma, ocular entrapment, conjunctival capillary dilatation, iris defects, retinal varicose veins and choroidal hemangiomas. Diagnosis The KTS triad is mostly described as: 1. Epidermal capillary malformations (usually wine-colored spots), which tend to have a focal distribution on one limb, do not necessarily involve the entire limb completely, and can occasionally be present in areas other than the hypertrophied limb. 2.Varicose veins and malformations, usually accompanied by lateral embryonic residual veins of the limb, may not have deep venous malformations. 3, bone and soft tissue hyperplasia, hypertrophy, can involve bilateral limbs, hyperplasia does not necessarily have to grow, thickening, can only be thickening of the bone cortex, increased bone density, and soft tissue hyperplasia can be unremarkable. If any two of the above features are met, the diagnosis can be made. If the diagnosis is difficult, X-ray examination has special diagnostic significance, which can find the growth and thickening of bone tissue on the affected side. Differential diagnosis This syndrome should be differentiated from Nonne-Milroy-Meige syndrome. Treatment Treatment should be individualized according to each patient’s presentation. For example, elastic bandage or cyclic decompression stockings are suitable for patients with mild symptoms or as an adjunctive treatment after surgical treatment; when there is spinal curvature or claudication, orthopedic shoes can be used to correct it; for small hemangiomas, electrocautery, cryotherapy, radiotherapy or laser therapy can be used; when there are varicose veins, arteriovenous fistulas, surgery is feasible, and when there is a big difference in the length of limbs, surgery is needed to correct them; when there is concurrent spinal cord pressure or subarachnoid hemorrhage, appropriate treatment should be carried out. When there is spinal cord compression or subarachnoid hemorrhage, corresponding treatment should be made. Prognosis Timely treatment, the prognosis is good. However, when spinal cord compression or subarachnoid hemorrhage occurs, or when there is necrosis of the limb or heart failure, improper treatment may bring serious consequences.