Venous Malformation

Venous malformation is the most common type of vascular malformation, affecting approximately 1 to 2 in every 10,000 people. These abnormal clusters of veins are present at birth and grow slowly with the child, often causing pain, swelling, and visible discoloration of the skin.

Table of contents

• What is a venous malformation?
• What causes venous malformations?
• How do venous malformations look?
• Signs and symptoms
• How are venous malformations diagnosed?
• Related conditions
• Treatment options
• Possible complications

What is a venous malformation?

A venous malformation (VM) is a place in the body where veins have not developed in the usual way. Instead of forming normally, the veins in a VM tend to be larger, more tangled, and shaped differently than healthy veins. These abnormal veins are widened or stretched out and do not work properly.^[1][2]

The blood vessel walls in a venous malformation are unusually thin and have relatively little smooth muscle around them, allowing them to stretch abnormally. This happens because these veins lack the normal structure and sometimes even the valves that prevent blood from flowing backward.^[5][8]

Venous malformations are the most common type of vascular malformation (abnormal blood vessel development), with a prevalence of about 1% in the general population.^[6] They can occur anywhere in the body, including the head, neck, limbs, trunk, and internal organs.^[2]

Children who have venous malformations are born with them, although the malformation might not be visible right away. A VM might not become noticeable until later when it has gotten bigger or its veins have stretched. Some venous malformations that are deep in the muscles or body might not be found until a child experiences pain or swelling.^[1][2]

Venous malformations grow slowly and steadily as a child grows. They increase in size proportionally, at the same rate as the child. Quick changes in the size or symptoms of these malformations may occur in certain situations such as surgery, trauma, infection, or hormonal changes during puberty, pregnancy, or menopause.^[2][7]

What causes venous malformations?

Venous malformations form before birth during pregnancy. They are thought to be caused by problems in the formation and development of the veins while the baby is still developing in the womb. Venous malformations are not caused by any drug, medication, or environmental factor that the baby may have been exposed to during pregnancy. No known food, medication, or activity during pregnancy can cause a VM.^[2][8]

These malformations result from an inborn error in blood vessel development, leading to the formation of abnormal endothelium (the inner lining of blood vessels). More than 90% of venous malformations result from a spontaneous genetic mutation (a change in the genes).^[9]

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 and has been found in families who have multiple family members with venous malformations. The PIK3CA mutation is not inherited.^[2]

Most cases have no clear cause, but a few are due to genetic conditions and may run in families. While venous malformations are often sporadic, familial inheritance patterns do exist in some cases.^[1][6]

How do venous malformations look?

A venous malformation close to the skin usually looks like a maroon, blue, or purple spot. The color of the malformation depends on the depth and amount of expansion of the affected blood 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.^[1][2]

Venous malformations are typically blue, soft, and compressible. When compressed, blood empties from the area and the malformation may look smaller or lighter in color. The color becomes more intense when a child is lying down as the lesion fills with blood.^[5][7]

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. They may involve shallow or deep veins or a combination of both. They can range in size from a very small lesion in one spot to widespread lesions that also affect the underlying tissue, muscles, and bones.^[2][8]

The appearance of venous malformations may change quickly. A bluish spot on the skin may get bigger during or after physical activity, or when the child is bearing down, crying, or in a position where the spot is below heart level.^[1]

Signs and symptoms

Venous malformations can appear anytime during childhood, adolescence, or adulthood. Most are present at birth, though they may not be apparent or diagnosed until later, especially if the malformation is small or not in an obvious location.^[8]

Children with a venous malformation may have these symptoms:

• One or more maroon, purple, or bluish spots on the skin
• A bulge or swelling in the skin with no unusual color
• A bluish spot on the skin that gets bigger during or after physical activity
• Pain
• Swelling
• Bleeding

The symptoms of a VM depend on the malformation’s size and location.^[1][8] Venous malformations can be confined to a small area or involve more than one body area. Although the skin or organs may be involved, these malformations are most often found in the cheek, jaw, tongue, and lips.^[7]

Smaller venous malformations that occur on the skin’s surface and do not cause pain may only require observation. However, more extensive lesions can cause significant morbidity, pain, and discomfort to patients.^[5][6]

How are venous malformations diagnosed?

Doctors usually diagnose a venous malformation based on a child’s health history, pictures and imaging of the VM, and a physical examination. Venous malformations can be confirmed through medical history and physical exam.^[1][7]

To learn more about how the VM is attached to other blood vessels and to see if internal organs are affected, the doctor may order imaging tests. The extent of the malformation is determined through imaging studies.^[1][7]

Common imaging tests include:

• An ultrasound, to check the structure and depth of a skin VM
• An MRI (magnetic resonance imaging), for a three-dimensional picture of the VM and to look for VMs in internal organs
• A CT scan (computed tomography), to create images of VMs affecting bones

These imaging approaches help doctors visualize the abnormal vessels and plan appropriate management strategies.^[1][6]

Doctors may also request blood tests to check for clotting problems. Patients with venous malformations are particularly susceptible to clots, as the blood flow is very sluggish in the affected veins. Blood tests may include PT (protime), PTT (partial thromboplastin time), fibrinogen, and D-dimer to check the severity of a clotting condition and monitor for potential complications. If blood test results are abnormal, consultation with a hematology specialist (a doctor who treats blood disorders) is usually recommended.^[3][12]

Related conditions

Some rare genetic conditions include venous malformations as part of a larger syndrome:

Blue rubber bleb nevus syndrome (BRBNS): Individuals with this syndrome have multiple rubbery blue lesions of the skin, which can vary in size from small to large. There are one or more VMs in the skin and the digestive tract. Lesions may occur in the gastrointestinal tract (the digestive system) including the mouth, stomach and intestines and on palms of hands and soles of feet. Pain or bleeding may occur.^[1][2]

Glomuvenous malformations (GVMs): These are venous malformations that contain glomus cells (nerve cells). Glomus cells in these malformations are shaped abnormally and cause them to be painful, particularly if touched. These bluish nodules can be painful or sensitive to cold temperatures. They’re usually near the fingers and toes, and may run in families. These lesions can be inherited and often are multiple.^[1][2]

Klippel-Trenaunay syndrome: This complicated disorder includes a combination of vascular anomalies, overgrowth of bone and other tissues, and varicose veins (enlarged, twisted veins).^[1]

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. Bone fractures and physical deformities may happen. Enchondromas may become cancerous over time so close monitoring is needed.^[2]

Cutaneomucosal venous malformations: Also called multiple cutaneous and mucosal venous malformations or VMCM, these VMs affect the skin and mucous membranes (moist areas of the body, such as the inside of the mouth).^[1]

Treatment options

Venous malformations can be very hard to treat, and often remain after treatment. They do not go away on their own and often recur after treatment. The choice of therapy is based on the appearance and symptoms of the particular venous malformation and can therefore be different over the course of a life. Complete removal is usually not possible.^[1][8][18]

Venous malformations are usually treated only if they cause pain or deformity, impair function such as vision or activities, or cause bleeding or other problems.^[1][4]

The treatment of venous malformations varies according to the depth, location, and extent of the lesion. Small lesions are observed over time and often do not require any treatment.^[5][7]

Treatment options include:

Conservative treatment: Compression garments can be used to control swelling or pain in lesions found in the arms or legs. Compression therapy with individually tailored compression stockings is particularly effective with lesions located just under the skin. If worn consistently during the day, it slows down the increase in volume over the years. Non-steroidal anti-inflammatory medication can reduce the pain caused by clotted vessels and help to decrease the tendency of the blood to clot.^[3][5][18]

Sclerotherapy: This is a common treatment approach where a scarring agent or solution is injected directly into the vein, which causes it to collapse and close off to blood flow. This procedure involves the injection of medication into blood vessels to shrink them.^[5][7]

Laser therapy: A laser is used to shut off the vein from blood flow. This treatment can be effective for certain types of venous malformations.^[7]

Surgical removal: Venous malformations are difficult to remove surgically. When necessary, extensive lesions can be partially removed. The remaining lesion may be treated with another form of therapy. Surgery is typically considered when other methods have not been successful or when the malformation causes significant functional problems.^[5][7]

Embolization: This highly specialized procedure involves the injection of small particles into the blood vessel to stop the flow of blood.^[7]

All of these procedures have risks that should be discussed with the physician. These risks must be weighed against the emotional and physical wellbeing of the child. Although smaller venous malformations can be adequately treated by one invasive treatment, a large number of patients require repeated treatments.^[7][18]

Possible complications

Some possible complications of venous malformations include:

• Pain when the VM suddenly expands if a clot forms
• Growth as the result of injury or during puberty
• Obstruction of vital functions like breathing or vision
• Fractures of the affected bone, and arthritis with limbs impacted by VMs
• Psychological and social issues related to the appearance of the lesion

Blunt trauma can cause the rupture of these weak dilated vessels, resulting in hematomas (collections of blood outside blood vessels). Patients with localized clots in their abnormal vessels may have prolonged clotting times and increased amounts of a clotting breakdown product known as D-dimer.^[3][8]

Venous malformations often lead to serious local and systemic complications. The blood flow is very sluggish in the affected veins, making patients particularly susceptible to blood clots. These complications can pose risks of increased blood pressure within these vessels.^[3][6]