Veins are a type of blood vessel whose purpose is to carry blood back to the heart. An abnormally-formed collection of veins is called a venous malformation, or slow-flow malformation. The veins in a venous malformation are formed irregularly before birth and become enlarged. They can occur anywhere on the body, from head to toe and may be seen in skin, mucosa (the lining of body cavities), subcutaneous tissue, muscle and rarely bone. They can be any size, from very small to affecting an entire arm or leg. Venous malformations are present at birth, but sometimes do not become apparent until later in life or after an injury. If the malformation is inside your child’s body, you may not see anything on the skin surface. A venous malformation can be diagnosed with an MRI, CT or ultrasound examination.
Venous malformations often look blue or purple in color, and usually, you can compress the area because they are soft. A venous malformation often increases in size when a child cries or strains. Usually, a venous malformation does not hurt, but it may become painful with pressure in the area or when a blood clot (thrombosis) forms in the area. Infection can also occur. Depending on the size and location of the venous malformation, other problems that can occur include pain, limitation in moving and normal function, disfigurement and a related clotting disorder.
Venous malformations may not require treatment if they are small. Larger and symptomatic lesions can be treated. Compression garments can be used as a treatment for venous malformations to decrease swelling and pain. Sclerotherapy is another treatment which can cause the collapse of the damaged vein, preventing further blood flow or clot formation. This therapy can shrink the size of the venous malformation. Surgical removal or partial removal is an option for some patients. Physical therapy may also be used as a treatment to maintain normal function. Children who have problems with blood clotting in the venous malformation may be put on medication such as aspirin or other blood thinners to prevent blood clot formation.