Types of Vascular Malformations in the Torso & Limbs

Vascular malformations are abnormalities in the blood vessels, including veins, lymph vessels, capillaries, and arteries. They are usually congenital, meaning they are present at birth, although some appear in the days and weeks after birth.

Some vascular malformations—such as a hemangioma, also known as a strawberry mark—are visible on the skin. They are not dangerous and may require cosmetic treatment or no treatment at all.

Other vascular malformations, such as arteriovenous malformations and venous malformations, are located inside the body. Some internal malformations have a corresponding sore or mark on the skin.

If an internal malformation grows unchecked, it can cause painful compression of nerves and organs; hemorrhage, or internal bleeding; and necrosis, or tissue death. Depending on the location of a vascular malformation and the structures it affects, it can also cause constipation, pelvic pressure, or swelling in the limbs.

Vascular specialists at NYU Langone diagnose and treat different types of vascular malformations of the abdomen, pelvis, arms, and legs.

Arteriovenous Malformations

Arteriovenous malformations, commonly known as AVMs, are abnormal tangles or clusters of blood vessels that can form wherever arteries and veins are located.

In an arteriovenous malformation, the capillaries—the tiny vessels that carry blood from arteries to veins and supply blood to the tissues—are missing. This causes a kind of “short circuit” in a person’s circulation, putting increased pressure on the arteries and veins and potentially weakening them over time.

Depending on their location, arteriovenous malformations can cause bleeding or organ compression. For instance, a malformation in the pelvis can cause bleeding in the uterus or bladder. A malformation in the abdomen may cause intestinal bleeding. If located in the chest, it can stress the heart.

Some arteriovenous malformations require treatment to prevent compression of nearby organs or to manage bleeding. For others, our doctors recommend monitoring without immediate treatment, called watchful waiting.

Venous Malformations

Venous malformations are the most common type of vascular malformation. They are caused by abnormal widening of the veins or a tangle of small veins that does not affect the arteries.

Venous malformations can occur near the surface of the skin or deep inside the body. If located near the surface, these malformations cause a lump beneath the skin and a corresponding bluish birthmark or skin lesion that is present at birth and becomes larger as a child grows.

Skin lesions caused by a venous malformation can be painful. If the skin that covers the malformation is very thin and becomes stretched as it grows, it can bleed. Blood can pool in the dilated veins, resulting in painful, but not dangerous, blood clots, known as thrombophlebitis.

Venous malformations often occur in people with Klippel–Trénaunay syndrome, a rare congenital condition that affects the development of blood vessels, soft tissues, and bones. Many people with this condition are born with a dark red birthmark called a port wine stain, which is caused by swelling in the capillaries near the surface of the skin.

Small venous malformations that aren’t a cosmetic concern or cause few symptoms may be monitored with watchful waiting.  Treatment may be recommended if a malformation is large or is causing symptoms, such as pain or bleeding.