Venous Malformations

Before Venous Malformation Intervention

Intervention for Venous Malformation

Venous malformations are comprised of slow-flowing, abnormal and dilated veins.  They are present at birth, but they are not always evident at birth. They appear as either a faint blue patch or a soft blue vascular mass. Most often, these lesions are located on the face, arms, legs, or trunk. They may frequently be confused with deep hemangiomas, and have often been incorrectly termed “cavernous hemangiomas.”

Venous malformations are the most common of the vascular malformations. They may occur incidentally as single lesions. There is some evidence to suggest a hereditary component when these lesions are multiple. Venous malformations may affect virtually any tissue type in the body, including skin, muscle, bone, and internal organs. They may also compress nerves, causing changes in sensation or motor control.

Venous malformations are easily compressible (flattened) and generally soft.  They tend to increase in size when they are in a dependent position. For example, a venous malformation of an upper extremity may swell when dangled. But when elevated, the blood will drain and the extremity will return to a more normal size.

Diagnosis of Venous Malformations

As with all vascular malformations, diagnosis depends on a thorough patient history and physical examination. A history of swelling and flattening of an area containing a malformation may indicate that it is of venous origin. Magnetic resonance imaging (MRI) provides much information as to the specific type and extent of a vascular lesion, including its relation to neighboring vital structures such as arteries and nerves. Treatment plans can be determined accurately based on physical findings and MRI results.

Venous Malformation Over Time

Venous malformations grow in proportion with the child, expand slowly, and often enlarge when the child experiences a growth spurt or takes oral contraceptive pills. Women will experience enlargement and worsening symptoms during pregnancy. Unlike lymphatic malformations, venous malformations rarely cause overgrowth when located in the limbs. Some reports have even cited cases of undergrowth in limbs affected by venous malformations.

Treatment for Venous Malformations

As with most slow-flow vascular lesions, treatment of venous malformations usually requires application of compression garments as the initial line of treatment when possible. This is true for most venous malformations of the extremities. The child is measured and fitted by a physical or occupational therapist.

Sclerotherapy is the mainstay of invasive treatment for venous malformations.  An interventional radiologist will inject a sclerosing agent, such as alcohol, into the abnormally dilated channels of the lesion under general anesthesia. This causes scarring and collapse of the vascular channels, preventing blood from pooling in these locations. Often, multiple sessions are required to address problematic areas of venous malformations. These sessions are spaced several weeks apart and may be required years down the line.

The decision to pursue sclerotherapy is largely dependent on the size and location of the venous malformation. This is determined in our multidisciplinary clinic, with input from all members of the Vascular Anomalies Team. The immediate complications of sclerosing include blistering, full thickness tissue loss, and possible nerve damage.

In select instances, the interventional radiologist may be able to treat a particular venous malformation with an endovenous laser (inside the vein). A probe is inserted into dilated venous channels, and the laser is then activated, causing obliteration of abnormal vessels.

Surgical excision of a venous malformation is performed on symptomatic areas and only when it can be done safely. As with lymphatic malformations, complete eradication of venous malformations is frequently not possible, and previously excised areas may re-expand. Therefore, several excisions may be required for large lesions that develop symptoms.

Complications of Venous Malformations

For venous malformations that involve or are located near the skin, varicosities may be quite prominent and result in a bluish discoloration of the skin.  Commonly, the massively dilated veins may cause blood to pool and stagnate, resulting in blood clot formation. These blood clots can become inflamed and painful. When this occurs, it is called "thrombophlebitis." Treatment centers on application of warm compresses, elevation of the extremity, and administration of anti-inflammatory medication (for example, ibuprofen). In some instances, this can lead to an infection (cellulitis) that will require antibiotics to treat. Repetitive bouts of thrombophlebitis can be distressing and will need to be addressed by more invasive means.  Clots may occur frequently and can eventually calcify and harden to form stone-like masses along the varicosities, called “phleboliths.” These masses can be felt when they are superficial. They generally do not cause problems for the patient, although many patients will discontinue use of their compression garments secondary to pain.