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Klippel-Trenaunay Syndrome

  • Klippel-Trenaunay syndrome (KTS) is a rare congenital (present at birth) vascular anomaly that results in your child having a large number of abnormal blood vessels.

    • No one knows the precise cause.
    • Klippel-Trenaunay syndrome is a complicated condition, and it affects different kids in different ways.
    • The first step is to have your child evaluated by members of an experienced interdisciplinary vascular anomalies team.
    • No single specialist can manage KTS and its associated problems, as different interventional techniques and surgical procedures are often needed.
    • Because there is no cure for KTS—and it’s a progressive condition—we believe that treating your child’s Klippel-Trenaunay syndrome symptoms  is the most effective way to manage the disease.

    How Boston Children's Hospital approaches Klippel-Trenaunay syndrome

    The Vascular Anomalies Center (VAC) at Boston Children's specializes in innovative, family-centered care for children with KTS. From your first visit, you’ll work with a team of professionals who are committed to supporting all your family’s physical and psychosocial needs.

    Children with KTS sometimes have legs that are so large as to be debilitating, forcing them to use a wheelchair. Surgeons at Boston Children's are leading the charge in removing the extra tissue that grows as a result of KTS. In what's called a debulking procedure, our surgeons remove a great deal of the extra tissue, which can allow your child to regain function of her leg. Read more about our treatment.

  • Klippel-Trenaunay syndrome is an exceedingly rare vascular anomaly that is already present when your child is born. Doctors can sometimes see evidence of KTS in a prenatal ultrasound, and the capillary malformation (in the form of a "port-wine stain") is almost always apparent at the baby’s birth. KTS is equally common in boys and girls.

    What causes Klippel-Trenaunay syndrome?
    No one knows the precise cause of KTS. Some doctors think it's caused by a mutation that occurs before birth (but not one that's inherited) in the cells that form the lymphatic system, veins and other tissues. No known food, medication or activity during pregnancy can cause Klippel-Trenaunay.

    Signs and symptoms of Klippel-Trenaunay syndrome
    KTS often has three characteristic signs:

    • capillary malformation covering one or more limbs (arm or leg)
    • hypertrophy—or excessive growth—of a limb (usually a leg)
    • abnormal blood vessels, including veins, capillaries and lymphatic vessels (vessels that drain fluid that leaks from arteries and veins and return that fluid to the bloodstream)

    What symptoms will my child have?
    KTS affects different kids in different ways. One child may have a mild form of the syndrome with a small capillary malformation and one hand or foot slightly larger than the other. Another child may have a capillary malformation that runs from her chest down her leg, lots of swelling and one limb that is much larger than the other.

    Here are some of the more common symptoms of Klippel-Trenaunay syndrome:

    • blood clots
    • cellulitis (infections in the skin)—your child may be more prone to infection because he is more likely to bleed easily as a result of the abnormal capillaries near the surface of his skin
    • anemia—due to blood loss because of easy bleeding
    • pain and heaviness of the affected limb—the pain can often be severe
    • difference in size between the affected and non-affected limb

    Are there any other signs of KTS?
    Some other signs of KTS include:

    • lymphatic abnormalities such as cysts and swelling
    • swollen veins

    Long-term outlook

    What is the long-term outlook for my child?
    Because there’s no cure for KTS, we focus on managing your child’s symptoms. The long-term outlook for your child depends on a few factors:

    • the extent of the disease
    • the amount of hypertrophy in your child’s limb or limbs
    • the abnormal blood vessels’ response to therapy
    • the overall health of your child
    • your child's tolerance of specific medications, procedures or therapies
    • new developments in treatment

    Every child is unique, and your care team will work with you to develop a treatment plan for Klippel-Trenaunay syndrome [MSP1] that works for your family.

    Does KTS get better?
    No. KTS is a progressive condition, which means that it will grow as your child grows. That said, many kids—especially those with mild cases of KTS—go on to live normal, healthy lives.

    What do we do after treatment is over?
    Depending on the severity of your child’s condition, your doctor may recommend a series of follow-up visits to check for complications and make sure that we’re managing the KTS effectively.

    A typical follow-up visit may include some or all of the following:

    • a physical exam
    • laboratory testing
    • imaging scans (e.g., MRI, CT scans, ultrasound)
  • How is Klippel-Trenaunay syndrome diagnosed?

    Doctors can sometimes see evidence of KTS in a prenatal ultrasound, and the capillary malformation (port-wine stain) is almost always apparent when your child is born.

    If your child is older and you believe he has KTS, doctors in our Vascular Anomalies Center will start with a complete medical history and a thorough physical exam. In many cases, that initial exam gives us enough information to diagnose KTS. If there’s any doubt, your doctor may recommend one or more of the following imaging tests, which can help determine the correct diagnosis and the appropriate next steps in treatment:

    • Magnetic Resonance Imaging MR or MRI —This high-resolution scan shows the extent of the hypertrophy of tissue and gives your doctor information about what problems it may be causing.
    • Ultrasound (also called ultrasonography)—An ultrasound helps your doctor see your child’s deep venous system to examine abnormalities.
    • Computed Tomography CT or CAT Scan —A CT scan shows detailed images of the area affected by KTS.

    After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options for KTS

  • Treatment for Klippel-Trenaunay syndrome (KTS) falls into several categories:

    Supportive care for Klippel-Trenaunay syndrome

    • Compression garments—Your doctor may recommend that your child wear tight-fitting pieces of clothing on the affected limb to reduce pain and swelling. They can also help protect your child’s limb from bumps and scrapes, which can cause bleeding.
    • Heel inserts—If your child’s legs are slightly different lengths (less than one inch difference), a heel insert can help your child walk normally.
    • Anticoagulant therapy—One of the biggest potential risks of KTS is that a blood clot formed in the abnormal blood vessels may break off and make its way to your child’s heart or lungs. Your doctor may recommend medications that thin your child’s blood to help prevent blood clots from forming.
    • Other medications—Your doctor may also recommend various pain medications and antibiotic medications for your child.

    Surgical care for Klippel-Trenaunay syndrome

    • Orthopedic CenterKTS can cause your child’s foot or leg to become excessively large; in some cases your doctor may recommend an operation.
      • An orthopedic surgeon can reshape your child’s foot to help him fit it into a shoe.
      • An orthopedic surgeon can perform a procedure called epiphysiodesis, which interrupts the growth plate and stops the leg from growing when it’s reached a certain length.
        • Our skilled orthopedic surgeons can estimate how long your child’s leg will be when it’s fully grown. Then, when the affected leg reaches that length, they perform this procedure to stop it from growing longer.

    We only perform epiphysiodesis if the expected difference between the length of your child’s legs is greater than an inch—and typically the operation is done when your child is between 10 and 14 years old.

    • Other surgeries—Your doctor may recommend one of these other surgical procedures if your child’s symptoms call for it.
      • A surgeon can remove some of your child’s excessive problematic veins.
      • A surgeon can also help reduce the size of your child’s affected limb with a debulking procedure, in which many of the abnormal vessels and some of the overgrown tissue is removed. 
    • Sclerotherapy —To help shrink and eliminate your child’s abnormal veins in the affected area, your doctor may propose the injection of an irritating solution, which causes the veins to collapse. One of our experienced interventional radiologists can perform this procedure.
    • Laser therapy—Pulsed dye laser treatments can help lighten your child’s capillary malformation (port wine stain). Laser treatment can also speed healing if your child’s lesion begins to bleed.

    What kind of support will we receive?

    At Boston Children’s we consider you and your child integral parts of the care team and not simply recipients of care. Your care team will be with you every step of the way to ensure that you and your child are getting the support you need.

    Your child's physician and other members of your care team will work with you to set up a schedule of follow-up visits.

    Rehabilitation for children with Klippel-Trenaunay syndrome

    Children with KTS often need multidisciplinary care. Some specialists your doctor may recommend for your child include the following:

    Depending on your child’s symptoms and the progression of the disease, we may also bring in the following specialists.

    • Physical therapists—KTS can affect your child’s arm or leg, making it hard or painful for your child to move it. A physical therapist can help ease the pain and increase your child’s range of movement.
    • Occupational therapists—Children with KTS sometimes get behind on developing motor skills because of physical problems related to the disease. An occupational therapist can get your child back on track.
    • Counselors—One characteristic of KTS is the typically large capillary malformation (port wine stain) on your child’s skin. As your child gets older, he or she may be uncomfortable with that skin lesion. One of our counselors can help your child deal with the psychological and social issues related to having a birthmark.
  • Boston Children's Hospital is home to the world’s largest vascular anomalies center. When doctors in other states or other countries need help diagnosing or treating vascular anomalies like KTS, they come to us. Here are some reasons why:

    Innovative treatment for KTS

    Traditionally, debulking—a surgical procedure where many of the abnormal vessels and some of the overgrown tissue is removed—has not been a standard treatment for kids with KTS. However, over the past 15 years, surgeons at Boston Children's Hospital have been performing large-scale debulking procedures to help kids whose overgrown legs have left them wheelchair-bound.

    Battling KTS at its source

    KTS is caused by errors that occur when blood and lymphatic vessels are forming.

    Our investigators are currently probing the genes and molecules that regulate the formation and growth of blood/lymphatic vessels. We hope that understanding the genes that control these molecular events will result in new therapies for vascular malformations.

    The Vascular Anomalies Center conducts research that may lead to the development of new, more effective therapies and perhaps ultimately result in ways to prevent these anomalies. Read more about our research.

  • Vascular Anomalies Center

    Boston Children's Hospital
    300 Longwood Avenue
    Fegan Building, 3rd Floor
    Boston MA 02115


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