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Vascular Malformations and Hemangiomas

What Are They?

Vascular Malformations are congenital abnormalities involving the arteries, veins or lymphatics. Nobody knows why Vascular Malformations occur and with one exception, they do not appear to be hereditary. The exception is the condition known as Hereditary Hemorrhagic Telangiectasia (HHT). Vascular Malformations are not caused by drugs or medications that the mother may have taken during her pregnancy, nor are they related to any environmental exposures during the pregnancy. Vascular Malformations are in reality benign tumors that contain abnormal collections of blood vessels and lymphatics. Both these structures are involved with the movement of blood and fluids in our bodies. They are divided into several categories, depending on the type of vessel involved. There are five different types recognized:

• Venous Vascular Malformations are ones where veins are involved. What one sees is a tumor containing irregular sized veins that form a mass. If the mass is cut open, one could see multiple small spaces, similar to a sponge. Venous Vascular Malformations cause pain especially when they become over distended with blood.
• Lymphatic malformations are collections of lymphatic spaces. Lymphatic fluid is fluid drained from the tissues but do not contain any blood.
• Venolymphatic malformations are a combination of both lymphatic and venous vessels forming a mass. The combination of venous and lymphatic malformations when affecting a whole limb is called Klippel-Trenaunay Syndrome.
• An Arteriovenous Vascular Malformation is where an artery connects directly with a vein without the normal capillaries in between creating a short circuit between the artery and the vein and causes a high flow connection.
• Hemangioma. These are commonly called port-wine stains and are made up of dilated tiny veins immediately under the skin hence the reddish color one sees in the skin.

All these types of Vascular Malformations can be considered to be part of the same family and so it is not uncommon for several members of the family to exist in one tumor. For example, it is not unusual to have a situation where a Venous Vascular Malformation also has arteriovenous component to it.

These Vascular Malformations are benign tumors and can occur anywhere in the body, including muscle, skin and various organs such as lung, liver, kidney, intestine and brain. Each site may present differently. Vascular Malformations often infiltrate surrounding structures such as muscle, ligaments, blood vessels and nerves and consequently they are not localized in a contained mass that can be easily cut away from the surrounding tissue and removed.

When Do They Present?

Vascular Malformations can present at any time. For example, hemangiomas are the most common noncancerous tumor of the skin. They often present at birth or appear a few months after birth. They are also known as a port-wine stain, strawberry hemangioma and salmon patch. Most are found in the head and neck area and occur five times more often in females than males. Infantile Hemangioma is a different type of tumor that occurs in an infant and can grow very rapidly but over time they get smaller and lighter in color. This process of involution can take several years.

Other types of Vascular Malformations, however, enlarge as the child grows and begin to cause symptoms later in childhood or as an adult.

What Are The Symptoms Of A Vascular Malformation?

Vascular Malformations can cause many different symptoms and often depend on the type and location in the body.

Venous Vascular Malformations can cause pain but this depends on where they are located and their size. They may also be visible as a lump that often enlarges and then gets smaller. Occasionally, the overlying skin may have a bluish tinge. Both the Lymphatic and Venous Vascular Malformations are thin walled and therefore prone to rupture especially with minor trauma. This can result in severe local pain and swelling.

Lymphatic malformations can become infected, requiring antibiotic treatments and possible surgery for drainage.

Arteriovenous Vascular Malformations may cause local pain but can also affect the heart, as there is a high flow of blood passing into this short circuit, making the heart work harder. Depending on their location, they may also cause bleeding, for example if they occur in the bowel, blood may appear in the stool. Arteriovenous Vascular Malformations in the brain may present as a stroke. Arteriovenous Vascular Malformations occurring in the lungs have different complications. The circulation through the lung acts not only to oxygenate the blood but also to filter small clots that may have developed in our limbs and body. If there is a short circuit between the lung artery and vein such as in a condition called Hereditary Hemorrhagic Telangiectasia (HHT) or as it is sometimes called Osler-Weber-Rendu syndrome, these small clots can pass into the general circulation and depending where they go can create severe problems. For example, passage of clots to the brain circulation could result in a stroke.

Port wine stain type of hemangioma seen in infants are asymptomatic and often resolve spontaneously on their own, but the Vascular Malformation known as Infantile Hemangioma may grow rapidly between birth and 3 months of age. The most important reason to treat these Vascular Malformations is that they may be associated with a low platelet count or contain a large arteriovenous shunt, causing a strain on the heart. They often resolve on their own as the child grows into adolescence but may require treatment to decrease the arteriovenous shunt to prevent heart failure.

How Are They Diagnosed?

Several imaging modalities may be necessary to obtain a full evaluation of the Vascular Malformation. Typically, an MRI is used to define the size and location of the Vascular Malformation and its relationship the surrounding body structures. An MRI can provide important information regarding the vascularity of the malformation as well. Ultrasound is sometimes employed in addition to the MRI if an Arteriovenous Vascular Malformation is suspected. Angiography is the most accurate method for determining the degree of blood flow through the Vascular Malformation. This procedure involves placement of a catheter into an artery for injection of x-ray dye and is performed when there is consideration for treating the arteriovenous portion of the Vascular Malformation (see below).

How Are Malformations Treated:

Vascular Malformations involving skin and muscle:

These are malformations that do not involve organs such as lung, liver kidney or brain. The Vascular Malformations referred to in this section involve the limbs, neck, chest wall and abdominal wall. Initially, surgery was the mainstay of treating Vascular Malformations but as you can imagine, these Vascular Malformations are often intertwined with normal structures such as muscles, arteries, veins and nerves. Trying to cut out the Vascular Malformations without causing significant damage to these structures can be especially difficult, considering the amount of bleeding that occurs. Over the last 20 to 30 years, treatment of these Vascular Malformations has been refined and today, most treatments involve direct injection of these Vascular Malformations using a number of medications. Once the diagnosis has been made on clinical history, imaging studies such as MRI and sometimes biopsy, several options are available. Current practice has shown that the most effective way of treating Vascular Malformations, is sclerozing embolization which involves the direct injection of sodium tetradecyl foam or occasionally alcohol into the tumor. This causes the destruction of the Vascular Malformation. In our practice, we often start with an angiogram to accurately determine whether an arteriovenous malformation is present. The reason for this is to ensure that when we inject the medication, there isn’t rapid flow that will wash out the medication before it can destroy the Vascular Malformation. The angiogram will accurately determine if there is a significant arteriovenous component present and if found, the branch arteries supplying the malformation can be blocked or embolized using a variety of substances such as plastic spheres or coils. This will not cure the Vascular Malformation but will substantially decrease the blood flow through it, allowing the subsequent sclerozing embolization to have the maximum effect. During the same procedure, we may obtain a biopsy to confirm the diagnosis, This is sometimes necessary as the MRI or ultrasound cannot always provide a definitive diagnosis for the mass and in a small percentage of patients, a misdiagnosis is possible based solely on the MRI or ultrasound appearance. The sclerosing embolization is performed two to three weeks later. This phase of the treatment is usually done under general anesthesia, as the injections can be painful. All procedures are performed in an outpatient setting and admission to the hospital is seldom necessary. There may be swelling at the treatment site for about three days. During this time, we give patients medication for any pain they may experience. Shrinkage of the tumor usually occurs within four to six weeks.

Vascular Malformations of organs:

Venous Vascular Malformations of organs such as liver or bone rarely require any treatment, unless they are large, making then susceptible to rupture and internal bleeding. Arteriovenous Vascular Malformations of brain, lung, liver, and kidney often do need treatment as their existence can cause serious problems such as stroke or internal bleeding. They can be effectively treated by performing an angiogram to evaluate the arterial blood supply and then performing catheter directed therapy using coils, plastic particles or special glue, as mentioned above.

Is The Treatment Successful?

This depends on the site treated. For example, lung Arteriovenous Vascular Malformations are very successfully treated by placement of special coils or plugs to close the connection between the artery and vein. Arteriovenous Vascular Malformations in other organs may be more difficult to treat as the tumor may recruit new arteries nearby which had not been plugged, perpetuating their presence. For the Venous Vascular Malformations, treatment is dependent on the venous spaces connecting with each other so that when the sclerozing embolization is performed, the medication passes into all the venous blood spaces. Occasionally, there may be pockets of venous spaces that do not connect with the space being injected and therefore will remain untreated. All vascular malformations require long-term surveillance so that if the patient develops further symptoms, the malformation can be reevaluated and further treatment initiated. The chances of a vascular malformation causing symptoms after treatment is dependant on its size. A larger vascular malformation has a higher likelihood to need further treatment in the future than a small one. Overall, the success of this approach for the treatment of vascular malformations is about 80%.

How New Is This Technique?

Interventional radiologists have used embolization techniques extensively for the last 40 years. They had been proven safe and reliable in treating Vascular Malformations. However, since Vascular Malformations are relatively rare and each tumor has its own nuances, their treatments are highly complex and should only be performed by Interventional Radiologists who have had extensive experience in their management and treatment. Dr. Aubrey Palestrant has treated Vascular Malformations for the last 31 years and has done well over 2000 procedures on these tumors. Vascular and Interventional Physicians and Dr. Palestrant works closely with other specialists in this field such as orthopedic and plastic surgeons and dermatologists to provide the best possible care to his patients.

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For more information please visit the Society of Interventional Radiology.

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