Could That Birthmark Be a Vascular Malformation? What Parents Should Know

An 8-year-old has what looks like a large purple stain on the side of her face that makes her feel self-conscious in front of other kids.

A high school soccer player has a small lump on his elbow that gets so painful when it’s bumped that he spends practices on the bench.

A 25-year-old woman has a chest X-ray and is diagnosed with a lesion, previously undetected, that is interfering with her heart function.

These sound like three very different conditions, but they are all versions of the same problem: a vascular malformation (VM)—a tangle of vessels that forms a noncancerous mass, which could be anywhere in the body. A VM is the result of a genetic mutation that occurs early in fetal development and is present at birth, although it is not always recognized until later in childhood.

VMs are rare and most are not life-threatening, but they can be complicated. They come in many forms, from what might appear to be a small, painless birthmark to a large lesion that may be located under the skin and deep within the body. In the latter case, it may be years before the VM is detected—it may not be discovered until adulthood. A doctor may suspect one when investigating a symptom such as unexplained pain or when a lesion is visible on an imaging test performed for another condition.

“Children with vascular malformations may not know how to describe a symptom like a body part that feels tender when it’s touched, especially if they are very young,” says Stacey Bass, MD, PhD, a Yale Medicine vascular and interventional radiologist, a specialist who provides image-guided, nonsurgical, catheter-based treatments as the primary approach to VMs. “And if they are a little older, they may be embarrassed to talk about it.”

A VM that is visible on the skin can make a child the target of bullying, and they don’t want to call more attention to it, adds Dr. Bass. “To make it worse, most parents don’t know about VMs and mistakenly attribute some of the symptoms to the child being active and getting bumps and bruises," she says.

Dr. Bass directs the Yale Vascular Anomalies Program, which focuses on detecting, monitoring, and treating all kinds of vascular anomalies. The Yale program cares for adults with newly detected VMs and those who were diagnosed in childhood. VM patients require lifelong care or monitoring, as VMs may recur and require multiple treatments and because some VMs can lead to serious health complications (more on that below).

The program also treats benign vascular tumors, or hemangiomas, which affect 4% to 5% of infants and often go away on their own or may be treated by a dermatologist.

Below, Dr. Bass answers five questions about the diagnosis and treatment of VMs.

Vascular malformations are abnormalities in the blood vessels (the tube-like channels, including arteries, veins, and capillaries, that carry blood throughout the body’s circulatory system) and/or lymphatic vessels (which carry lymphatic fluid, including white blood cells that help fight invading bacteria). A VM is a disorganized cluster of these vessels—similar to tangled Christmas lights (only with vessels instead of wires)—that develops before birth.

Each VM is different, and symptoms can be wide-ranging. Some people don’t experience any symptoms. For others, a mild case could appear as a small lump or a port-wine stain (a birthmark that is a flat patch of red/purple skin).

In a more serious case, the VM could result in an abnormal communication from veins to arteries, essentially creating a short circuit. This can result in stress on the heart as it tries to manage the extra blood flow, Dr. Bass says. Depending on the location, some severe VMs can lead to difficulty swallowing or walking. Some can even cause heart failure or stroke.

The major categories of VMs include:

• Venous malformation: This is a collection of dilated, misshapen veins that can occur either deep in the body or shallowly, visible on the surface of the skin as a blue-purple discoloration. This falls into a category known as a “slow-flow malformation,” meaning that venous blood flows slowly through the affected vessels. Unless it is visible, this type of VM tends to be identified later in childhood, often when symptoms are triggered by an injury or physiological changes, such as growth spurts or puberty. Symptoms vary based on the location of the lesion and can range from minor aches and pains to bouts of bleeding and clotting disorders.
• Lymphatic malformation: Another slow-flow malformation, this is a cluster of cyst-like structures involving vessels that contain lymphatic fluid. These clusters may start to cause problems during infancy and childhood, when the fluid can pool and create cysts that may appear as a growing lump, often in the head and neck area, sometimes covered by what looks like small blisters on the skin. Other than the visible lump, a lymphatic malformation can cause a range of symptoms, depending on its location, from constipation (if it’s in the gastrointestinal tract or pelvis) to wheezing and trouble breathing (if it’s located on the chest) to bone loss (if it develops in the bones). It can also bleed or get infected and quickly become red and painful.
• Arteriovenous malformation (AVM): A disorganized tangle of blood vessels that occurs most frequently in the brain and spinal cord, this type of VM disrupts the normal connections between vessels, bypassing tissue that needs oxygenated blood and causing tissue damage and the death of nerve cells. An AVM is a “fast-flow malformation,” meaning that the blood flows faster through the malformation and can cause the heart to work harder. It is often diagnosed when a person is in their 20s and sometimes during pregnancy. Symptoms are wide-ranging, from none to mild pain and muscle weakness, to seizures and even loss of consciousness. AVMs carry a danger of hemorrhage if damaged due to their high-flow characteristics.
• Capillary malformation: Characterized by a port-wine stain, these slow-flow VMs are caused by tiny blood vessels that have formed abnormally in the superficial layers of the skin. They also grow larger as the person ages. In most cases, they don’t cause serious symptoms, but they may grow thicker and darken over time.
• Fibroadipose vascular anomaly (FAVA): This rare, slow-flow complex venous malformation affects a part of the muscle, typically in an arm or leg. These VMs are most often diagnosed in older children, teenagers, or young adults, more often in the lower extremities, and are more common in women than men. FAVAs can cause intermittent or constant pain, swelling, and restricted movement. The pain can also occur far from where the FAVA is located.

Vascular malformations can be associated with one of several mixed congenital syndromes. For instance, people with Klippel-Trenaunay Syndrome will have a combination of the following: port-wine stains, bony and/or soft tissue overgrowth, and/or slow-flow venous/lymphatic malformations.

Another example is Blue Rubber Bleb Nevus Syndrome, which is associated with multiple isolated slow-flow venous malformations on the skin and in the underlying tissue, as well as in the intestines and other internal organs.

A VM that is not visible can take years to detect. When symptoms, such as pain or lumps, arise, misdiagnoses are common, says Dr. Bass, who has had patients who consulted multiple specialists before coming to her.

Sometimes, a VM located deep in the body and with no symptoms is detected incidentally when a patient undergoes imaging for another condition. It might be found with an ultrasound, CT scan, or MRI.

“Some VMs are easily detected because they can be quite disfiguring, especially in the head and neck region—those may even be discovered with imaging before a baby is born,” Dr. Bass says. VMs that are close to the skin’s surface are also easy to detect—they may appear as a blue, purple, or maroon spot, or as a bulge or swelling with no abnormal color.

“Most VMs end up getting diagnosed and treated in childhood due to signs and symptoms, including pain, areas of discoloration, or growth disturbances when one limb grows longer than another,” Dr. Bass says. Diagnosis may also be triggered by some sort of change or rapid growth in the malformation, such as during a growth spurt or puberty.

Less commonly, VMs are diagnosed in adulthood.

“Just as each patient is unique, so are their malformations—no two are created the same,” says Dr. Bass. “Therefore, each patient gets an individualized treatment approach that takes into account such factors as their malformation type, location, and symptoms.”

Sclerotherapy is a common treatment approach that uses a very small needle to inject a medication into the malformation that will cause it to shrink and collapse. It results in a small scar that does not allow blood or lymphatic fluid to collect as easily. Typically, a few sessions are needed to establish the desired effect of less pain and disfigurement. “Depending on the anatomy of the lesion, this can be very effective right away, or sometimes it takes advanced methods to get it under control,” Dr. Bass says.

Certain types of VMs, such as FAVA, are associated with a bulky overgrowth of nearby fatty tissue. This VM can be very effectively treated using another strategy, called cryoablation. This works by placing small probes into the lesion that deliver an ice ball to freeze the abnormal tissue. This is followed by thawing out the ice ball. The freeze-thaw cycle results in the destruction—and eventual shrinkage—of the abnormal tissue and pain relief over the next several weeks of healing.

There are other types of VMs, such as capillary malformations, that are limited to the skin surface. These can be disfiguring, especially when they are located on the face. In this situation, the patient would be referred to a dermatologist to determine if they could be treated with laser therapy, which uses heat to destroy the abnormal blood vessels without damaging the surrounding skin, potentially in multiple treatments.

Depending on the type and severity of the malformation, patients cared for by the Yale Vascular Anomalies Program also have access to many other specialists, including hematologists; different types of surgeons; ear, nose, and throat specialists; orthopaedists; and physical therapists. Sometimes, patients will need more than one type of treatment for their VM—and maybe more than one specialist.

“The VAP [Vascular Anomalies Program] members meet regularly to discuss patients needing a multidisciplinary approach to treatment, whether it be a vascular malformation, hemangioma, or other type of anomaly,” says Dr. Bass. “In this way, the individual patient is ‘seen’ by a multitude of specialists, while clinic visits are kept to a minimum and children don’t have to miss school.”

There are medical therapies available to patients with vascular malformations.

Sirolimus (Rapamune®) is a drug that has been used for over a decade to treat kids and adults with various types of vascular malformations (mostly lymphatic and venous malformations).

Alpelisib (VIJOICE®) is one of the newest treatments for VMs; it was approved by the Food and Drug Administration (FDA) in 2022 for use in children ages 2 and older through adulthood with specific types of severe vascular lesions linked to a mutation in the PIK3CA gene. These drugs, which are also used to treat cancer, work by blocking signals that cause overgrowth and abnormalities in certain body tissues; they can decrease the size and rate of vascular growth.

Surgery is also an option for patients; however, it is difficult to fully remove most VMs because they are typically incorporated into the normal surrounding tissues. “Often, the surgical scar and the need to take out a lot of normal tissue makes surgery a last resort,” adds Dr. Bass. “However, there are some very well-defined, small lesions that can be easily taken out surgically with little risk of recurrence.”

No matter how they are treated, VMs can recur, and long-term follow-up care is important for VM patients. “For example, we may be able to treat a 9-year-old girl whose VM is causing elbow pain, but she could end up coming back in a year when she—and her VM—undergo a growth spurt,” Dr. Bass says. “But, in this case, the goal is to use the tools we have available to manage the pain, so she can play field hockey without constantly guarding her arm or being afraid someone is going to touch it. For most of these patients, it's not about a cure; it’s about symptom control.”

VMs can cause both physical and emotional pain. “Some children report feeling different because of it,” Dr. Bass says. “Other kids don't even really realize what's going on. They just know something hurts or that kids are picking on them for having a purple spot or visible lump. This is all the more reason for people to be aware of VMs and detect them when children are young, before the lesion grows and before the child starts to experience any negativity around it,” Dr. Bass says.

Enrolling in a program, such as the Vascular Anomalies Program at Yale, will ensure that the child is cared for holistically, adds Dr. Bass. “Emotional support through counseling and child life services should be a part of any care plan for these complicated patients,” she says.

A VM can also be stressful for parents, who may worry they did something to cause the problem or passed on a gene that is at fault. “I provide reassurance that the majority of VM mutations are not inherited," says Dr. Bass. “I'll say to parents, ‘Maybe your child was born with a freckle on their shoulder; do you have that same freckle? Of course not. You didn’t pass that freckle on any more than you passed on the VM. So, just think of the VM like another freckle that we need to take care of.’”

I try to provide perspective and positivity because, most of the time, vascular malformations are not life-threatening; they just need to be managed, she adds.