What is a venous malformation?

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.

In rare cases, the tendency to develop venous malformations can run in families, and in such families a mutation in the gene TIE2 (or TEK) can be found.  Clinical testing for this genetic mutation is not generally available, although in some centres it can be performed as part of a research program.

It use to be thought that venous malformations were an ‘error of development’ and while this is sort of true, we now understand that venous malformations are caused by mutations in particular genes.  In nearly all cases this is not an inherited mutation as is seen in families, but what is known as a somatic mutation, which means a mutation in the DNA which occurs when the genetic code is copied from cell to cell during development.  In most patients with venous malformations, therefore, there is little to no risk of developing similar lesions elsewhere or of passing the condition on to later generations.

What problems do venous malformations cause?

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.

What treatments are available for venous malformations?

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 used to guide a needle into the malformation and x-rays to confirm where the injection goes.  The radiologist will select which injection material is most suited to the situation.  The injection material collapses 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.

The drug Sirolimus (or Rapamycin) has proven to be an effective treatment for some patients with venous malformations.  It is most effective in relieving pain.

More recently, a group of drugs called PI3Kinase inhibitors are being used to treat venous malformations.  These drugs were initially developed to treat cancer, but there is reason to think they may be effective in treating many venous malformations.  There is promising early data to suggest that this may be the case, and it is hoped that clinical trials will start soon in Australia.

Propranolol is of no use in the treatment of venous malformation.

What is a ‘Glomuvenous malformation’ or glomangioma?

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.

What is Klippel-Trenaunay syndrome?

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.  Klippel-Trenaunay syndrome has been shown to be caused by a somatic mutation in the gene PIK3CA and is now considered to be part of a spectrum of disease known as ‘PIK3CA related overgrowth spectrum’ or PROS.  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 these children 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.

What is ‘Blue Rubber Bleb Naevus Syndrome’?

This is a very 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.