FAQs—Vascular Malformations and Sclerotherapy
Vascular malformations are the other type of vascular birthmark, and are entirely different from hemangiomas. They can occur anywhere in the body. They can occur in isolation or as part of another disease. Typically, the malformation grows in proportion with the child and may not be noticed for months or years. Often they cause little to no problems. Sometimes the mass may start growing out of proportion, occasionally from a triggering factor like trauma, puberty, or pregnancy, though often no triggering factor is identified. Some malformations can however grow rapidly, so if a vascular malformation is suspected that child should be referred to a vascular birthmark specialist for evauation.
Vascular malformations can be broken down into several sub-groups depending on what type of vessel is involved. Vessel types include: venous malformations, lymphatic malformations, arterial malformations, capillary malformations, or a combination of these types.
Venous malformations are one of the most common vascular anomalies. A VM is an abnormal formation of tangled, dilated veins somewhere within the body. These abnormal veins often lack smooth muscle along the vessel wall, causing them to enlarge and rupture easily. The center of the tangled veins is called the nidus. There are a few options for treating VMs depending on the size, location, and type of symptoms the person is having. Usually, VMs are not treated unless there is a perceived risk, like possible rupture, or if the person is symptomatic. The two most common methods of treatment are surgery and sclerotherapy. Surgery is the gold standard. Complete removal of the VMs’ nidus is required to achieve an effective cure. Depending on the mass’ size and location, this can be very challenging if not nearly impossible by surgery alone. Sclerotherapy uses a chemical solution to cause destruction of the blood vessel walls and rapid thrombosis, or clotting of the nidus. Typically, sclerotherapy involves a simple injection through a small needle into the mass but it takes several treatments before it is effective.
Arteriovenous malformations (AVMs) are abnormal connections between arteries and veins. They are believed to be caused by a mistake in the formation of the normal arterial-capillary-venous connections that occurs during early pregnancy. The cause of most AVMs is not known. In childhood, the blush of an AVM can be mistaken for hemangioma. AVM becomes obvious as signs of fast blood flow appear. The skin may become a darker red or purple color, veins nearby may enlarge, a mass may appear beneath the birthmark, a pulse may be felt, and the area may be warm.
There are some genetic syndromes which are associated with AVMs. One is called hereditary hemorrhagic telangiectasia (HHT or Rendu-Osler-Weber syndrome). Affected children usually present with telangiectasia of the skin and mucous membranes (mouth and gastrointestinal tract). AVMs can also occur in the lungs, liver, and brain. Parkes Weber syndrome involves an AVM of a limb with overgrowth of that limb. The affected limb usually has a capillary malformation as well. When the amount of blood passing through the AVM is very large, the heart is affected because it has to handle more blood flow (high-output cardiac failure). AVM are treated techniques such as embolization, sclerotherapy, surgery, or a combination of these techniques.
Lymphatic malformations (previously known as cystic hygromas) can be seen on ultrasound before the baby is born. It is critical that you arrange for your baby to be evaluated at a medical center with a vascular birthmark team who can work with your obstetrician to ensure a safe delivery and newborn period. Treatement involves sclerotherapy and/or surgery.
Capillary malformations (previously known as port wine strains) are flat and pink in the newborn period. Laser therapy can be very effective in young children to fade the lesion.
Each type of malformation is treated differently and even two malformations of the same type need an individualized treatment plan depending on the size, location and symptoms. The treatment plan must be specialized for each patient and usually required coordination by a number of different specialists on the vascular birthmark team.