In this section
A venous malformation is a swelling caused by a collection of abnormal veins. If they are in the skin, they usually appear blue. Deeper venous malformations may not be visible and may just show themselves as pain and/or a swelling. They can occur anywhere in the body and vary in size from very small to very large.
We believe that venous malformations are caused by an error in development which happens when the body is growing in the womb, and so they are present from birth, although we might not be aware of them till later. The error occurs when the genetic material in each cell in the body has an error when the gene code is copied from one cell to another, so all the cells derived from that cell also carry the error.
Most venous malformations are not inherited. In about 1% of cases, venous malformations can be found in many members of the same family. In these inherited cases, people who are affected will often have more than one malformation. In these families with multiple venous malformations, it is possible to test for the gene error but this test is not currently available routinely.
The two problems that most often occur with venous malformations are altered appearance and pain. The altered appearance is caused by the swelling and colour of the malformation. The pain seems to have different causes. It sometimes is due to blood clots forming in the malformation. This happens because the blood flows so slowly through the large vessels. Pain of this sort tends to be intermittent, difficult to predict and hard to treat.
The two main treatments for venous malformation are injection sclerotherapy and surgery. Injection sclerotherapy is generally performed under anaesthetic by an interventional radiologist experienced in this field. Ultrasound is used to guide a needle into the malformation and then x-rays are used to confirm where the injection goes. The radiologist will select which injection material is most suited to the situation. The injection material collapses and seals the veins to stop them filling with blood. Surgery can also be helpful in the treatment of venous malformations, especially when they are within muscle.
Low dose aspirin, taken under the direction of a doctor, can be useful in reducing episodes of pain due to blood clotting.
There are new drug treatments available for this condition which appear to be very promising. Preliminary trials of the drug Rapamycin (sirolimus) in the treatment of venous malformation are underway in several centres including Melbourne. Propranolol is of no use in the treatment of venous malformation.
Glomuvenous malformations or glomangiomas are blue swellings found typically in the skin. They are often multiple and often run in families. They are usually tender if pressed and can sometimes be quite painful. They do not reach the large size sometimes seen with venous malformations. The best treatment is to remove them by surgery if they are causing problems. They generally do not respond to injection treatment but can sometimes be effectively treated by laser.
Klippel-Trenaunay syndrome is a condition where a large vascular malformation, usually a venous or a mixed venous lymphatic malformation affects most or all of one limb, and ‘overgrowth’ of the limb occurs. (Note: Many children who have been labelled with Klippel-Trenaunay syndrome in the past do not have Klippel-Trenaunay syndrome.) When the syndrome is present children can have a range of problems including psychosocial, pain, bleeding, deep vein thrombosis, pulmonary thrombosis and leg length discrepancy. When one leg grows significantly more than the other, this can cause chronic back problems. Treatment by an experienced paediatric orthopaedic surgeon, if timed correctly, generally results in both legs being similar in length in adulthood. The growth of the limb should be carefully monitored through childhood. Patients with Klippel-Trenaunay syndrome require the dedicated care of a multidisciplinary team. Treatment is lengthy and complex, often involves multiple specialists and requires a long term strategy.
This is a rare condition in which children have large numbers of small blue skin lesions similar to venous malformations. They also have similar lesions in the gut which can bleed and cause severe anaemia (low blood count). Blue rubber bleb naevus syndrome should always be considered in a child who has venous malformations in the skin and anaemia.