VASCULAR ANOMALIES AND MALFORMATIONS

Vascular Malformations (sometimes referred to as 'vascular Anomalies') occur where a section of the vascular system develops abnormally. Sometimes these malformations are immediately apparent and sometimes they become more noticeable later in life.

There are many different types of vascular malformations, depending on the section of the vascular system affected. They can be classified according to where they occur, namely whether they are located in the capillaries (the smallest blood vessels), in the lymphatic system, in the veins or in the arteries. Some malformations can affect more than one location.

These locations are also categorised by the volume of blood flowing through them. Malformations in the capillaries, veins and the lymphatic system are classified as 'low flow' and Malformations in the arteries and the intersections between arteries and veins are classified as 'high flow'.

How each type of malformation is described can be a little confusing, as the terminology used has changed over time.

Arteriovenous malformations ('AVM')

As the name implies, this type of malformation involves veins and arteries and is classified as a high flow malformation. They appear as swelling under the skin which often feels warmer than the surrounding skin and sometimes with a discernible 'pulse' as blood flows through the malformation.

Venous malformations

Venous malformations occur where one or more veins (sometimes in clusters) dilate abnormally. After birth, these veins can continue to dilate slowly, cause discolouration and distortion of the skin above. People with venous malformations can be more prone to thromboses (i.e. blood clots) due to the slow flow of blood through the affected veins. Due to the potential of complications arising from blood clotting, venous malformations should be monitored and if necessary, treated.

The main types of vascular malformations are:

Haemangioma

Haemangiomas are benign tumours of vascular origin, usually seen in early childhood. The term haemangioma is often applied to other vascular malformations.

There are two types:

Congenital haemangiomas are fully formed at birth, do not grow and generally shrink over time
Infantile haemangiomas are more common and tend to grow from birth for the first year of life.

Haemangiomas may be located just under the skin or in the fat layer beneath the skin but may also be located elsewhere in the body such as in muscles or organs.

Lymphatic malformations

These malformations affect the lymphatic system, which carries a clear liquid (called 'lymph') around the body. Lymphatic malformations are cysts containing lymph fluid which can range in size from small to large (ie the size of a small water balloon and can occur anywhere in the body.

Symptoms

Most Vascular Malformations are immediately apparent as masses or under the skin or discolouration of the skin. Depending on the type, some can cause symptoms such as:

pain and tenderness

Swelling

Bleeding

Ulceration

Skin infection

Tests / Diagnosis

The first step is a physical examination. The most common tests used to diagnose the extent of vascular malformation is an MRI (Magnetic Resonance Imaging scan), although CT scans and ultrasound scans may also be recommended. Sometimes an angiogram (a type of X-ray using contrast dye injected into the blood vessels) can help map the malformation.

Treatment

In many cases vascular malformations that do not cause any discomfort do not need to be treated, although it is often recommended that they be monitored. Where there is the possibility of blood clot formation, treatment may be recommended, normally this is medication to minimise blood clotting. Other treatments may include:

Embolisation

This involves blocking abnormal blood vessels.

Sclerotherapy

This involves the injection of medication into blood vessels causing them to shrink.

Laser therapy

This treatment can remove superficial malformations.

Surgery

Surgery is generally recommended for the removal of deep malformations. It may be combined with embolisation.