Vascular Malformation

Vascular malformations are abnormal changes in blood vessels that are usually present from birth, though they may not become visible until childhood or even adulthood. These conditions can affect any blood vessel in the body and range from harmless birthmark-like marks to serious problems requiring treatment.

Table of contents

• What Are Vascular Malformations?
• Where They Occur in the Body
• Types of Vascular Malformations
• Difference from Hemangiomas
• What Causes Vascular Malformations
• Signs and Symptoms
• How They Are Diagnosed
• Treatment Options
• Living with Vascular Malformations

What Are Vascular Malformations?

Vascular malformations are abnormalities that involve blood vessels. The word vascular refers to blood vessels, which are the tubes that carry blood throughout your body^[1]. These changes are typically present at birth but frequently may not become evident until later in life during childhood or even in adulthood^[1].

These conditions are quite rare, with some types found in less than 1 percent of the population^[2]. Many types of vascular malformations don’t cause symptoms until they are triggered by such events as adolescence, pregnancy, or some major surgery, trauma or injury^[2]. Over the years, malformations can grow larger and become problematic depending on what type of vessel is involved^[2].

Vascular malformations are comprised of abnormally formed channels within a vascular apparatus that are lined by cells called endothelial cells and do not undergo abnormal cellular turnover. They are present from birth, often go unnoticed at birth, never regress, and grow proportionally with the individual^[5].

Where They Occur in the Body

Vascular malformations can develop in any part of your body — from your head to your toes^[1]. They may present as a soft tissue mass, pain, swelling and/or skin discoloration^[1]. Some vascular malformations develop on your face or neck or near your brain or spinal cord. Others look like birthmarks or red blemishes^[1].

• Arteries and arterioles
• Capillaries
• Veins and venules
• Lymphatic channels
• Brain
• Spinal cord
• Face and neck
• Skin

Vascular malformations can affect any blood vessel in your circulatory system. They may also develop in lymphatic vessels in the lymphatic system, which is a network that helps your body fight infections and remove fluid^[1].

Types of Vascular Malformations

Healthcare providers determine the type of vascular malformation based on the affected blood vessels. Vascular malformations are grouped together based upon their common embryological origin of having a single endothelial cell lining^[5]. There are four major categories based on their flow characteristics: slow-flow (capillary malformation, venous malformation, lymphatic malformation) and fast-flow (arteriovenous malformations)^[5].

Venous malformation: The most common type of vascular malformation, a venous malformation, develops in a vein. Veins carry blood back to your heart to get oxygen^[1]. These are the most common vascular malformations and can occur anywhere in the body^[2].

Arteriovenous malformation (AVM): An AVM is a tangle of arteries and veins that connect incorrectly. Instead of connecting to capillaries, the arteries pump blood directly into the veins through a cluster of channels called a nidus^[1]. AVMs can affect your brain or spine^[1]. The blood circulating within the malformation flows very fast^[15].

Capillary malformations: These involve the capillaries, which are the smallest blood vessels, and are the most common type. They used to refer only to port-wine stains but now include others^[8]. Capillary malformations are limited to the superficial layers of the skin but they can thicken, become nodular, and sometimes become disfiguring^[8].

Capillary telangiectasia: These small areas of enlarged capillaries tend to develop in the brain. Most capillary telangiectasias don’t cause problems. But occasionally, they cause a hemorrhage^[1].

Cavernous malformations: Tightly packed capillaries in your brain have long “caverns” (cavernous malformations). Blood moves slowly through these caverns^[1].

Lymphatic malformations: Dilated lymphatic channels forming fluid-containing cysts tend to develop in the soft tissues of your face, neck and axillary (arm pit) regions^[1]. These are congenital, developing from badly-formed lymphatic vessels in early embryonic development. Abnormal development of the lymph vessels results in their failure to connect and drain into the venous system^[8].

Difference from Hemangiomas

Vascular malformations and hemangiomas result from irregularities in blood vessels (vascular anomalies). They both can cause birthmark-like blemishes, but there are differences^[1].

Hemangiomas are a type of noncancerous (benign) vascular tumor. They form when blood vessels clump together underneath the skin. Strawberry hemangiomas typically appear after birth. They grow rapidly for the first six months of an infant’s life. These tumors rarely cause problems and usually go away without treatment. When hemangiomas are large or affect function or cause pain or other problems, they usually can be managed with a medication that makes them shrink faster. Only very rarely is surgery necessary^[1].

Vascular malformations are present at birth but may not be noticeable until childhood or even adulthood. They grow slowly and may extend deeper into nearby tissues and structures, causing problems. Vascular malformations frequently require treatment^[1].

What Causes Vascular Malformations

Vascular malformations are thought to result from developmental errors during embryogenesis, such as abnormal signaling processes that control apoptosis, maturation, and growth of vascular cells. These errors lead to the persistence of vascular plexus cells with a certain degree of differentiation^[5].

The cause of vascular malformations often isn’t known, though they can be inherited in some families^[4]. Most vascular malformations are present at birth (congenital) and occur by chance (sporadic) similar to a birthmark^[6]. Although, there are a few types that can be inherited as a family trait^[6].

Rarely, vascular malformations develop during adulthood after trauma or another incident^[1].

Signs and Symptoms

Some vascular malformations may be very noticeable, slightly noticeable or not noticeable at birth. Vascular malformations will grow with time^[6]. Some vascular malformations can become prominent suddenly due to illness or some may become more prominent gradually during periods of growth such as adolescence or pregnancy^[6].

Symptoms depend on the type of central nervous system vascular malformation and where it’s found. Some vascular malformations have no symptoms. They may be found on imaging done to look for another condition^[9].

Symptoms for some central nervous system vascular malformations may include bleeding, seizures, headache, and brain and nervous system problems^[9].

Vascular malformations can be small, focused in one area of the body, or they can be large, involving several areas of the body. Vascular malformations may range from asymptomatic to seriously symptomatic. Serious symptoms include difficulty walking or moving, pain, swelling, blood clots, muscle weakness, and, if it is located in the head and face, problems with seeing, breathing, or swallowing^[6].

If you have a lymphatic malformation, your symptoms will depend on the size of the malformation and where it is located. Symptoms may include a soft, smooth lump on the skin that may or may not have discoloration, a lump or mass that gets larger quickly, a lump that shows signs of infection, chronic small bumps, blisters, or bloody crusts on the surface of the skin that may rupture and ooze blood or clear lymph fluid^[6].

Vascular malformations that cause pain, impair function such as vision or activities or cause bleeding or other problems may need treatment^[1].

How They Are Diagnosed

After a thorough history and physical exam, the doctor’s first step is to determine whether the abnormality is, in fact, a vascular malformation, and not another type of vascular abnormality such as a hemangioma^[2].

A person can have a single isolated vascular malformation or one that involves several vessels. In some cases, a vascular malformation turns out to be part of a more complex syndrome that features multiple disorders and affects multiple organs^[2].

Typically, doctors will order imaging studies to help with diagnosis. Imaging studies may include ultrasound, MRI, and/or angiography, an imaging procedure that involves the injection of dye that will outline the blood vessels on an X-ray^[2].

The diagnosis of these lesions can be made with a complete clinical history and exam and confirmed with Doppler ultrasound or magnetic resonance imaging (MRI)^[13]. In the opinion of some specialists, MRI with contrast is the method of choice because of its incomparable soft tissue visualization, which is used to determine the location, extension, and relationship with surrounding important structures, such as nerves, orbits, and airways^[13].

Before a baby is born, a lymphatic malformation may be found during an obstetrical ultrasound or Fetal MRI, which provide pictures of a fetus within the uterus. A lymphatic malformation on the skin may be found during a physical examination. Imaging is needed to confirm the malformation^[6].

Treatment Options

Treatment for vascular malformations depends on the type of the malformation. Each type of malformation is treated differently^[14]. Some indications for treatment include pain, disfigurement, cosmetic improvement, limb length discrepancy and muscle atrophy, impingement on other organs, and heart failure. Not all lesions need to be treated, especially in asymptomatic patients, and expectations for outcomes need to be well managed because, in some cases, a complete cure may not be possible^[13].

Treatments can close the affected blood vessels^[1]. Vascular malformations that are symptomatic may require treatment. Both diagnosis and treatment will depend on your specific type of vascular malformation^[6].

Laser therapy is usually effective for capillary malformations or port wine stains, which tend to be flat, violet or red patches on the face^[14]. Laser therapy works by directly targeting abnormal blood vessels with laser light^[22].

Arterial malformations are often treated by embolization (blood flow into malformation is blocked by injecting material near the lesion)^[14]. Arteriovenous malformations are typically treated by guiding a tiny catheter within the blood vessels into the abnormal area and delivering a special type of glue to shut down the abnormal communication between the artery and the vein^[15].

Venous malformations are usually treated by direct injection of a sclerosing (clotting) medication which causes clotting of the channels^[14]. Venous and lymphatic malformations are typically treated by injecting a chemical called a sclerosant directly into the abnormal area, causing the area to shrink and usually improving symptoms^[15].

Surgery was performed for 22 cases (17.9%) of venous malformations and arteriovenous malformations in one study^[11]. Most often, a combination of these various treatments is used for effective management of the lesion^[14]. Fewer than 10 percent of children and adults with tumors or malformations will require surgery^[22].

It is not uncommon for multiple treatments to be necessary to achieve the desired result when treating any of these malformations^[15]. Treatment of vascular malformations is an integral part of multidisciplinary approaches^[11].

Living with Vascular Malformations

Vascular anomalies can pose a considerable challenge to patients in their everyday lives and may also lead to psychosocial problems. As a result of the rarity of the diseases, competent specific medical advice on topics concerning daily life is not easy to find^[16].

Vascular malformations, while rare, can be devastating. Most are picked up in childhood, where pain and disfigurement can result in long-lasting disabilities and emotional distress^[2]. Many families are sent to multiple physicians before finding a vascular anomalies specialist^[2].

In addition to medical centers of expertise with interdisciplinary experience in the subject, contact with patient support groups can be a great advantage^[16]. The best way to treat vascular anomalies is to address them as early as possible in a child’s life. Benefits of early treatment include less chance of psychological trauma, local anesthetic can be used instead of sedation, and lower risk of reoccurrence^[22].

Vascular malformations don’t shrink or go away without treatment. Patients should see a craniofacial doctor with experience in treating vascular malformations^[4]. Certain questions affect patients with vascular malformations in their everyday life to the extent that they have to consult a general practitioner^[16].