Vascular Malformations- Cardiology, Dermatology, Diagnostics, Ear Nose And Throat (ENT), General Surgery, Medical Genetics, Neurosurgery, Pediatrics, Plastic and Cosmetic Surgery

What Are Vascular Malformations?

Vascular malformations result from abnormal development in large blood vessels (like veins and arteries), smaller vessels (like arterioles and venules), tiny capillaries, and the lymphatic channels that transport white blood cells and lymphatic fluid away from the arteries and veins.

Although they are typically present at birth, they frequently do not appear until later in life, possibly even in adulthood. This is because vascular malformations grow slowly as opposed to hemangiomas, which go through growth cycles and then regress.

Depending on the vessels involved, malformations can continue to expand and become problematic over time. They can be minor and insignificant or very serious, even potentially fatal.

Types Of Vascular Malformations

Medical professionals can identify the type of vascular malformation based on the affected blood vessels. The most common types of vascular malformations are:

  • Venous Malformation
  • Capillary Malformation
  • Lymphatic Malformation
  • Arteriovenous Malformation
  • Mixed

Venous, capillary, and lymphatic malformations are slow-flow, which means that the affected blood vessels have slow blood flow.

Arteriovenous malformations (AVMs) are fast-flow vascular malformations. Fast blood flow from arteries to veins typically occurs through a nidus, a collection of abnormal vascular channels. Rapid blood flow in a large AVM can put the heart under stress and raise the risk of heart failure.

Now, let's take a closer look at each of these.

Venous Malformation

A venous malformation develops in a vein, a vessel that carries blood back to the heart to get oxygen. This is the most prevalent type of vascular malformation, affecting 1% to 4% of people.

Clinically, they present as bluish, soft, compressible lesions typically found on the face, limbs, or trunk. The involved veins are dilated, giving them their blue color. They can be isolated or part of a syndrome, most commonly Klippel-Trenaunay Syndrome.

Capillary Malformation

Port wine stains, also known as capillary vascular malformations, are birth defects that appear as irregular patches of pink or purple skin on the head, body, or extremities. The dilated capillary vessels in the skin's dermis give the color pink.

Capillary malformations are found in 0.5% of the population. The dilated capillaries in the skin enlarge and darken with age.

The majority of capillary telangiectasias are not harmful. However, they can sometimes result in bleeding. These may, in rare cases, be a symptom of underlying abnormality.

For instance, sometimes spinal abnormalities are linked to a capillary malformation over the spinal column. Likewise, a more profound vascular abnormality in a child's arteries, veins, or lymphatic system, such as Klippel-Trenaunay syndrome, can be concealed by a capillary malformation.

And rarely, if the stain covers a portion of the forehead and upper eyelid, the baby should be examined for neurological issues as it may be a sign of the highly uncommon condition known as Sturge-Weber syndrome.


Lymphatic Malformation

A lymphatic malformation is a relatively rare vascular malformation consisting of fluid-filled channels or spaces that are thought to result from the lymphatic system's abnormal development.

Usually, these birth defects become visible when the child is two years old. Though they can affect any part of the body (aside from the brain), lymphatic malformations most frequently involve the head and neck.

Arteriovenous Malformation

An arteriovenous malformation is an abnormal network of blood vessels that connects the arteries and veins, bypassing the capillary network.

Blood leaves the heart through arteries and travels through the rest of the body before returning via veins to the heart. The exchange between the blood in the arteries and veins occurs in the capillaries, where the minor blood vessel units of arteries and veins connect with each other.

By directly connecting the arteries and veins, an AVM obstructs this process. AVMs can result in severe medical issues and excruciating pain. The tangled blood vessels that make up the AVM are also prone to deterioration and rupture.

Although they can develop anywhere in the body, arteriovenous malformations are most frequently found in the brain, spinal cord, and extremities. Arteriovenous malformations in the internal organs, such as the kidneys, intestines, and lungs, are uncommon but possible. For example, if the AVM ruptures in the brain, it may result in brain bleeding (hemorrhage), a stroke, or permanent brain damage.

Most AVM types are not inherited, and a family history of AVMs can rarely raise your risk. However, the risk of AVM may be increased by certain hereditary conditions. These include Osler-Weber-Rendu syndrome and hereditary hemorrhagic telangiectasia.


Mixed vascular malformations often result from lymphatic and venous components, arising together in a single, complex disorder.

Causes Of Vascular Malformations

The majority of vascular malformations are caused by localized or regional abnormal development of lymphatic or vascular channels during fetal development. Usually, they are present at birth.

Less frequently, an injury that causes undetected vessel damage over time may become a vascular malformation. Venous malformations may also become apparent for the first time due to an injury or hormonal changes during puberty or pregnancy.

Rarely individuals inherit genetic alterations (mutations) that increase the risk of vascular malformations. However, more is still being discovered about these genetic causes.

Some syndromes that may accompany vascular malformations are:

  • Klippel Trenaunay syndrome
  • Generalized lymphatic anomaly
  • Parkes Weber syndrome
  • Cowden syndrome
  • Gorham's (or Gorham-Stout) syndrome
  • Sturge-Weber syndrome
  • Blue rubber bleb nevus syndrome
  • Cobb syndrome
  • Rendu-Osler-Weber syndrome
  • Wyburn-Mason syndrome

Symptoms Of Vascular Malformation

Different vascular malformations have various symptoms. For example, vascular malformations in the skin may resemble a raised red, purple, blue, black, or brown birthmark. These marks could bleed, swell up, or cause pain.

Unless it bleeds, an AVM in your brain might not show any symptoms. However, bleeding AVMs in the brain can cause seizures, headaches, muscle weakness, or paralysis on one side of your body.

Pain, body aches, swelling, organ damage, and issues with blood clotting can all be brought on by venous malformations.

How Is A Vascular Malformation Diagnosed?

The doctor will take a detailed medical history and perform a thorough physical examination. After this, the first step will be to ascertain whether the abnormality is a vascular malformation and not another type of vascular abnormalities like a hemangioma, a benign tumor, or noncancerous growth of the blood vessels.

Sometimes, vascular malformations are accidentally discovered in utero during routine ultrasounds. For example, a parent commonly notices a new lump on their child's leg, arm, or trunk. In addition, vascular malformation may occasionally be a part of a more complex syndrome that includes various diseases and affects multiple organs.

Medical professionals use specialized imaging procedures to observe blood flow and look for vascular malformations. These imaging tests consist of the following:

  • Simple X-rays.
  • MRI, such as an MR Angiogram (MRA).
  • Ultrasound, including vascular ultrasound.
  • CT scans, including CT angiogram.
  • Venogram or angiogram.

Treatment Of Vascular Malformations

As many vascular anomalies are incredibly complex, doctors will employ a collaborative approach to diagnosis and treatment. The best management is a team approach comprising healthcare providers that are experts in pediatrics, plastic surgery, pediatric orthopedics, and endovascular surgery.

Vascular malformations are typically treated by reducing symptoms and averting complications. However, treatment may not be necessary for malformations that don't pose a threat; they can be monitored over time.

Treatments depend on the blood vessels that are affected. They frequently involve surgically severing, closing, or removing the affected blood vessels. However, minimally invasive techniques can be used to treat the majority of malformations.

Simple observation with regular follow-up visits can also help with minor vascular malformations. In addition, healthcare providers may occasionally advise a biopsy to confirm the diagnosis or to collect tissue for genetic analysis.

The most common techniques used for the treatment are:


Embolization is a technique for blocking the blood vessels in an AVM. This is done by interventional radiologists, who treat patients with image-guided procedures.

Sometimes the malformation needs to be surgically removed, or it can be treated with radiation using a technique called radiosurgery. In these situations, embolization is the first procedure doctors perform to shrink the malformation and lower the risk of bleeding.

During embolization, a small tube, known as a catheter, is guided up using an X-ray. The catheter is placed in the leg's femoral artery treatment area.

A neurological examination is conducted before and after administering a small dose of medications. This can help determine whether the AVM's vessel also supplies healthy and significant brain areas. The catheter is then removed after the injection of a permanent agent into the AVM. Each vessel feeding the AVM must go through this process again.

The patient is awake during the procedure but is kept at ease by the anesthesia team, which monitors and administers medications via an intravenous line. The patients typically spend the night in the Neurological Intensive Care Unit following the embolization to be closely watched.

Patients typically spend three nights in the hospital for each embolization and usually need two or three procedures spaced two to six weeks apart.

After discharge, patients can immediately resume their regular full-time activities. However, after the embolization, there might be some nausea from the medications that were given or a slight headache from the clotting of the blood vessels of the AVM.


Doctors can treat lymphatic and venous malformations with sclerotherapy. First, through the skin, a substance is injected into the malformation.  Then, a substance to irritate the vessel wall is applied. This method creates a blood clot, effectively stopping the flow of blood in the area. The malformations are then destroyed by inflammation of the inner wall, and the body replaces them with sclerosis—a type of scar tissue. Additionally, it removes the noticeable scars that are disfiguring after surgery.

Laser Therapy

The superficial portion of a deep malformation and superficial venous malformations can be successfully treated with laser therapy. Lasers that can reduce the bluish discoloration of the skin and the lining of the lips and mouth are typically used during treatment.

The vascular malformation is treated through intact skin using a laser and a cooling device. Additionally, laser therapy can be combined with sclerotherapy, and surgery, to successfully treat mixed venous malformations

Lasers are also used to treat lymphatic malformations, mainly tiny blisters on the tongue's surface and in the mouth's lining.


Surgery may be necessary either before or following embolization or sclerotherapy. If the condition is severe, doctors only remove enough tissue to stop it from happening again while avoiding disfigurement.

 Sometimes doctors follow surgery with angiography scanning to see if they need to perform embolization for more long-term stability.

Complications And Outlook

Some malformations do not cause any issues. However, malformations are more likely to result in pain and swelling.

Due to pain or the involvement of muscles, nerves, or joints, some malformations make it challenging to exercise, work, play sports, or perform daily activities.

Heart failure may eventually result from large, high-flow malformations.

Vascular abnormalities in solid organs, like the kidney, uterus, or liver, can cause complications and organ dysfunction.

The amount of oxygenated blood that reaches your brain can be decreased by vascular abnormalities like AVMs in your brain or spine. In addition, there may be life-threatening issues, such as:

  • Aneurysms.
  • Strokes.
  • Bleeding into the brain or intracranial hemorrhage.

Most malformations can be treated, and they generally respond positively to it. However, vascular malformations can impact appearance and self-esteem, which can cause depression and anxiety. In addition, if more severe malformations like AVMs in the brain start to bleed, they could be life-threatening.

The Bottom Line

Vascular malformations are rare disorders of the blood vessels that are frequently present at birth. Although the possibility of recurrence, medical professionals can treat vascular malformations using catheter-based techniques such as embolization and sclerotherapy.

Blood loss brought on by AVMs that form in your brain or spine can be fatal. You should talk to your healthcare provider about preventive measures if you have a genetic condition that increases your risk of vascular malformations.


  • Cox, Joshua A et al. “Vascular malformations: a review.” Seminars in plastic surgery vol. 28,2 (2014): 58-63. doi:10.1055/s-0034-1376263
  • Carqueja, Inês M et al. “Vascular malformations: classification, diagnosis and treatment.” International angiology : a journal of the International Union of Angiology vol. 37,2 (2018): 127-142. doi:10.23736/S0392-9590.18.03961-5

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