Klippel-Trenaunay syndrome


Klippel-Trenaunay (klih-PEL tray-no-NAY) syndrome ― also called KTS ― is a rare disorder found at birth (congenital) involving problems in the development of certain blood vessels, soft tissues (such as skin and muscles), bones and sometimes the lymphatic system. The main features include a red birthmark (port-wine stain), ranging in color from pink to reddish-purple, atypical vein or lymphatic development (malformations), and overgrowth of tissues and bones. These findings most often affect one leg but may occur in an arm or elsewhere.

Although there is no cure for KTS, treatment goals are to improve symptoms and prevent complications.


People who have KTS may have the following features, which can range from mild to more extensive:

  • Port-wine stain. This pink to reddish-purple birthmark is caused by extra tiny blood vessels (capillaries) in the top layer of skin. The birthmark often covers part of one leg but can involve any portion of the skin. It may get darker or lighter with age.
  • Vein malformations. These include swollen, twisted veins (varicose veins), usually on the surface of the legs. Deeper malformed veins in the arms, legs, abdomen and pelvis also can occur. There may be spongy tissue filled with small veins in or under the skin. Malformed veins may become more prominent with age.
  • Overgrowth of bones and soft tissue. This begins in infancy and may be limited to one leg, but it can occur in an arm or, rarely, in the trunk or face. This overgrowth of bone and tissue creates a larger and longer extremity. Rarely, there may be fusion of fingers or toes or extra fingers or toes.
  • Lymphatic system malformations. The lymphatic system — part of the immune system that protects against infection and disease and transports lymphatic fluid — can be malformed. Extra lymphatic vessels can be present that don't work properly and can lead to fluid leakage into the tissues and swelling.
  • Other conditions. KTS can also include cataracts, glaucoma, hip dislocation at birth, purple-red skin coloring when cold and blood-clotting problems.

When to see a doctor

KTS is usually identified at birth. It's important to get a prompt, accurate diagnosis and appropriate care to treat symptoms and prevent complications.


KTS is a genetic disorder. It involves genetic changes (mutations), most commonly in the PIK3CA gene. This gene is responsible for the growth of cells and the development of tissues in the body. A change in this gene results in overgrowth of tissues.

KTS is not usually inherited. The gene changes occur randomly during cell division in early development before birth.

Risk factors

Family history doesn't seem to be a risk factor, so it's unlikely that parents of one child with KTS will have another child with the disorder, even if one of the parents has KTS.


Complications of KTS can result from atypical development of blood vessels, soft tissues, bones and the lymphatic system. These can include:

  • Port-wine stain complications. Some areas of the port-wine stain may thicken over time and may form blisters (blebs) that are prone to bleeding and infections. Skin ulcers and poor wound healing also may occur.
  • Vein malformations. Varicose veins can cause pain and skin ulcers due to poor circulation. Deeper malformed veins can increase the risk of blood clots (deep vein thrombosis) and cause a life-threatening condition called pulmonary embolism if the clots dislodge and travel to the lungs. Venous malformations in the pelvis and abdominal organs can cause internal bleeding. Superficial veins can develop less serious but painful clots and inflammation (superficial thrombophlebitis).
  • Overgrowth of bones and soft tissue. Overgrowth of bone and tissue can cause pain, a feeling of heaviness, limb enlargement and problems with movement. Overgrowth that causes one leg to be longer than the other can result in problems with walking and may lead to hip and back problems.
  • Lymphatic system malformations. Malformations in the lymphatic system can cause fluid buildup and swelling in the tissues of the arms or legs (lymphedema), skin breakdown and skin ulcers, leakage of lymphatic fluid, or infection of the layer under the skin (cellulitis).
  • Chronic pain. Pain can be a common problem that results from complications such as infections, swelling, bone involvement or vein problems.


Diagnosis of Klippel-Trenaunay syndrome begins with a physical exam. Referral to a vascular malformations specialist is helpful for evaluation and treatment recommendations. During the evaluation your health care provider:

  • Asks questions about your family and medical history
  • Does an exam to look for swelling, varicose veins and port-wine stains
  • Visually evaluates growth of bones and soft tissues

Several diagnostic tests can help your doctor evaluate and identify the type and severity of the condition and help determine treatment. Some tests include:

  • Duplex ultrasound scanning. This test uses high-frequency sound waves to create detailed images of blood vessels and blood flow.
  • MRI and magnetic resonance (MR) angiography. These procedures help differentiate between bone, fat, muscle and blood vessels and can identify malformations.
  • Scanogram. Also called scanner photography, this X-ray technique creates images of bones and helps measure their lengths.
  • CT scan or CT angiography. A CT scan creates 3D images of the body that help show blood clots in veins.
  • Contrast venography. This procedure involves injecting a dye into veins and taking X-rays that can reveal atypical veins, blockages or blood clots.
  • Coagulation studies. These tests can help evaluate how the blood clots.
  • Genetic studies. These tests can identify the characteristic pattern of gene differences (gene signature) that may explain why the condition occurred.


Although there's no cure for KTS, your doctor can help you manage symptoms and prevent complications.

Because KTS may affect many systems in the body, your health care team may include specialists in vascular medicine and surgery, skin diseases (dermatology), interventional radiology, orthopedic surgery, physical therapy and rehabilitation, and other areas as needed.

You and your doctor can work together to determine which of the following treatments are most appropriate for you. Treatments may include:

  • Compression therapy. Bandages or elastic garments are wrapped around affected limbs to help prevent swelling, problems with varicose veins and skin ulcers. These bandages or elastic garments often need to be custom-fit. Intermittent pneumatic compression devices — leg or arm sleeves that automatically inflate and deflate at set intervals — may be used.
  • Skin care. Skin hygiene of the affected limb can reduce infection risk and be part of treatment for superficial bleeding.
  • Physical therapy. Massage, compression and limb movement as appropriate may help relieve lymphedema in arms or legs and swelling of the blood vessels.
  • Orthopedic devices. These may include orthopedic shoes or shoe inserts to compensate for differences in leg length.
  • Epiphysiodesis (ep-ih-fiz-e-OD-uh-sis). This is an orthopedic surgical procedure that effectively can stop length overgrowth of the lower limb.
  • Embolization. This procedure, performed through small catheters placed into the veins or arteries, blocks blood flow to certain blood vessels.
  • Laser therapy. This procedure may be used to remove or lighten port-wine stains and to treat leaking and bleeding blebs on the skin.
  • Laser or radiofrequency ablation of veins. This minimally invasive procedure is used to close off malformed veins.
  • MR-guided ablation. Blood vessels are treated with a laser or cautery under MRI guidance.
  • Sclerotherapy. A solution is injected into a vein, which creates scar tissue that helps close the vein.
  • Surgery. In some cases, surgical removal or reconstruction of affected veins, removal of excess tissue, and correction of the overgrowth of bone may be beneficial.
  • Medication. Some people have benefited from oral medications that may help to treat complex vascular and lymphatic malformations that cause symptoms. But these drugs may have significant side effects that require monitoring. Topical sirolimus may help relieve symptoms of superficial vascular malformations. Studies are ongoing to determine the effectiveness and safety of these medications in people with KTS.

In addition, treatment may be needed for complications such as bleeding, infection, blood clots or skin ulcers. Special care may be needed during pregnancy to prevent complications.

Lifestyle and home remedies

Strategies to help manage KTS symptoms include:

  • Keep appointments. Regularly scheduled appointments can help your doctor identify and address problems early. Ask your doctor about what schedule of appointments is appropriate for you.
  • Use orthopedic shoes, if recommended. Orthopedic shoes or shoe inserts may improve your physical function.
  • Follow your doctor's recommendations on physical activity. Encouraging use of affected limbs as appropriate may help relieve lymphedema and swelling of the blood vessels.
  • Elevate affected limbs. When possible, raising your leg or other affected limb can help reduce lymphedema.
  • Notify your doctor of changes. Work with your doctor to manage your symptoms and prevent complications. Contact your doctor if you have symptoms of blood clots or an infection or if you experience increased pain or swelling.

Coping and support

Living with KTS can be a challenge. Support and advocacy groups can provide a connection with other people who have KTS. The K-T Support Group and other organizations provide educational materials, resources and information about connecting with others. Ask your doctor if there is a local support group in your area.

Talking with a psychologist, psychiatrist or other mental health professional also may be helpful to many people with KTS.

Preparing for an appointment

Most cases of KTS are found at birth. If the doctor suspects that your child has this syndrome, diagnostic tests and treatment will likely begin before your child leaves the hospital.

Your child's doctor will look for developmental problems at regular checkups and give you the opportunity to discuss any concerns. It's important to take your child to all regularly scheduled well-baby visits and annual appointments.

Here's some information to help you prepare.

What you can do

If your doctor believes your child shows signs of KTS, basic question to ask include:

  • What diagnostic tests will be needed?
  • When will I get the results of the tests?
  • What specialists might be needed?
  • What medical conditions related to this syndrome need to be addressed right now?
  • How will you help me monitor my child's health and development?
  • Can you suggest educational materials and local support services related to this syndrome?

What to expect from your doctor

Your child's doctor will ask you a number of questions, such as:

  • What symptoms does your child have that concern you?
  • Has your child had any procedures or treatments for these symptoms?
  • Has your child had any previous difficulty with infections or blood clots?
  • Did you have any problems with your pregnancy or your child's birth?
  • Can you tell me about your family's medical history?
  • Is your child having any problems dealing with family, social activities or school?

Your doctor will ask additional questions based on your responses, symptoms and needs. Preparing and anticipating questions will help you make the most of your time with the doctor.

Content From Mayo Clinic Updated: 02/11/2022
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