Health Library
Venous Malformations

What Are Venous Malformations?

Venous malformations are the most common vascular malformation. They consist of a abnormally formed or misshaped or stretched-out veins that do not work properly. Venous malformations increase in size proportionally (at same rate) as a child grows. Quick changes in the size or symptoms of these malformations may occur in certain situations such as surgery, trauma, infection or hormonal changes (puberty, pregnancy or menopause). They may occur anywhere in the body.

Venous malformations form prior to birth. They are thought to be caused by problems in the formation and development of the veins during pregnancy. Venous malformations are not caused by any drug, medication or environmental factor that the baby may have been exposed to during the pregnancy. Some may not be noticed until teenage years or adulthood.

Some people with venous malformations have been found to have a genetic change in the TIE-2 or PIK3CA gene. The TIE-2 mutation may be inherited. It has been found in families who have multiple family members with venous malformations. The PIK3CA mutation is not inherited.

What do venous malformations look like?

Venous malformations can be confined to a small area or involve more than one body area. A person may have one malformation or multiple separate lesions. Venous malformations may involve shallow or deep veins or a combination of both.

The color of the malformation depends on the depth and amount of expansion of the affected vessels. Shallow lesions tend to have a maroon-red or purple color. Deep lesions appear bluish. A very deep lesion may have no color and appear as a swollen mass or may not be visible at all.

The appearance of venous malformations may change quickly. When the child is crying, bearing down, or active, the lesion may visibly expand in size and become more intense in color. Color may also change with different environmental temperatures.

How are venous malformation diagnosed?

A medical history and physical examination are used to diagnose a venous malformation.

They swell when the area involved is lowered below the level of the heart (placed in a dependent position). Lesions that are in the head / neck region get bigger when the patient “bears down” or tries to force air from the lungs with the vocal cords closed (Valsalva maneuver). They are generally soft to the touch but can feel hard if a blood clot forms in the malformation. Venous malformations may be painful.

Radiologic imaging such as ultrasonography, magnetic resonance imaging (MRI), or computed tomography (CT or CAT scan) may be needed to confirm diagnosis or to see the full extent of the malformation. MRI is helpful to figure out if the malformation goes into a joint.

Venous malformations of the stomach and intestines can be seen using telescopic equipment inside of the involved organs ((endoscopy)). For patients who are age 6 years or older, capsule endoscopy may be performed. This is when a camera is placed in a pill and swallowed.

Conditions Involving Venous Malformations

  • Glomuvenous malformations. These are venous malformations that contain glomus cells. Glomus cells are nerve cells that cause these malformations to be painful, particularly if touched. These lesions can be inherited and often are multiple.
  • Blue rubber bleb nevus syndrome. Individuals with this syndrome have multiple rubbery blue lesions of the skin, which can vary in size from small to large. Lesions may occur in the gastrointestinal (GI) tract including the mouth, stomach and intestines and on palms of hands and soles of feet. Pain or bleeding may occur. Treatment options include endoscopic and surgical removal and medications.
  • Maffucci's syndrome. This syndrome includes venous malformations and multiple enchondromas (noncancerous growths) of bones. Most people do not have symptoms during childhood. Before puberty, patients develop a hard nodule (small, localized growth), on a finger or toe, which is usually followed by more nodules on the arms, legs, hands and feet. Venous malformations occur anywhere on the body. Bone fractures and physical deformities may happen. Enchondromas may become cancerous over time so close monitoring is needed.

What are the possible complications of venous malformations?

Venous malformations may cause pain or swelling of the affected area or extremity. Slow blood flow and pooling in abnormally dilated veins (venous ectasias) may lead to unusual sensations such as heaviness, numbness or tingling of the involved arm or leg.

Abnormal blood flow may also cause skin ulcers, muscle cramping or joint pain when walking. Individuals with large or multiple venous malformations may have blood abnormalities that increase the risk of bleeding and clotting. Blood clots (phleboliths) within superficial venous malformations can cause inflammation and pain. The malformation may increase the risk of developing blood clots in the deep veins (deep vein thrombosis, DVT), which is a serious medical condition.

If these deep blood clots travel to the blood vessels of the lungs (pulmonary emboli, PE), this can be life-threatening. Venous malformations involving the pelvic area may cause bleeding from the bladder, GI tract / rectum, or genitalia.

Treatment and Management

Should my child receive treatment?

Individuals with venous malformations should complete an evaluation by a doctor who has expertise in management of patients with vascular malformations. Treatment decisions must be made on an individual basis.

How are venous malformations managed?

Management of venous malformations varies. Treatment is mostly supportive. Regular follow up is important.

Treatment options include:

  • Observation. Small malformations with little cosmetic or functional issues are often watched over time without treatment.
  • Compression garments. This involves wearing a tight-fitting garment on the affected body part (if possible) to prevent pain or growth of the malformation.
  • Sclerotherapy. This includes putting a medication directly into the malformation to shrink or close off the abnormal veins. This procedure is generally done to decrease pain.
  • Laser therapy. The shallow skin part of a venous malformation may be treatable with a laser. Several treatments six to eight weeks apart are necessary. This procedure is most commonly done to improve the look of the affected skin.
  • Surgical options. Surgical options vary from person to person. Small lesions may be removed entirely by surgery. Large or complex lesions may be partially removed.
  • Drug therapy. Medications may be used in large, diffuse or complicated venous malformations or when surgical procedures are not an option.
    • Low molecular weight heparin (enoxaparin, Lovenox): This medication is injected under the skin. This is a blood thinner that can improve pain caused by phleboliths (superficial clots in the malformation). It is also used to prevent or treat dangerous blood clots.
    • Oral anticoagulation (ex. rivaroxaban, apixaban): These medications are given by mouth. These blood thinners can improve pain caused by phleboliths (superficial clots in the malformation). They are also used to prevent or treat dangerous blood clots. Not all patients may take these medications.
    • Oral sirolimus: This medication is taken by mouth. Oral sirolimus may be helpful in improving pain, swelling, and blood abnormalities that increase the risk of bleeding and clotting.
    • Investigational drugs- Additional medications are currently being studied in research.

Are there any risks associated with treatment?

Each treatment approach has drawbacks and limitations.

  • Sclerotherapy. Blistering, scarring, infection, numbness or tissue loss may occur. The malformation may shrink but then reappear or grow over time. Or the malformation may not respond to sclerotherapy treatment at all.
  • Laser therapy. Scarring or changes in skin pigmentation could potentially occur.
  • Surgical options. Some scarring will occur with surgical removal of the malformation. Surgical excision may cause damage to structures involved with the lesion such as nerves, normal blood vessels, and muscles. Any malformation that was not completely removed may enlarge over time. Bleeding during surgery is a known complication.
  • Drug therapy.
    • Low molecular weight heparin (enoxaparin, Lovenox): The most common side effects are bruising and / or irritation or pain at the injection site. There is an increased risk of bleeding.
    • Oral anticoagulation (ex. rivaroxaban, apixaban): There is an increased risk of bleeding.
    • Oral sirolimus: Before starting, your doctor will discuss all possible side effects of this medication.

Last Updated 03/2022

Reviewed By Denise Adams and Dr. Kiersten Ricci, MD

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