Vascular Malformations

The doctors at SEVS have considerable experience for over 15 years in managing a range of vascular lesions, from intracerebral lesions to the lesions of the body and limbs. Their experience includes clinical and imaging assessment of these lesions. They are amongst the most experienced practitioners in this country in embolization techniques, with a wide variety of embolic materials. The group has a wide experience of sclerotherapy for low flow lesions, again with a diverse range of sclerosant materials.


Vascular lesions comprise a varied group of entities which are now grouped as vascular tumours and vascular malformations. They are frequently jumbled and confused due to overlapping names in the older literature. In particular haemangioma and AVM are still frequently used to refer to almost any vascular lesion.


In modern terminology haemangioma only refers to a vascular tumour of infancy. These are treated by multidisciplinary paediatric groups such as that at The Children’s hospital Westmead.


Vascular malformations most frequently occur as isolated lesions and can occur almost anywhere in the body. Sometimes however they are components of more complex syndromes such as Klippel Trenaunay syndrome, Von Hippel Lindau syndrome (Heriditary haemorrhagic telangiectasia), Sturge Weber syndrome) and Parkes Weber syndrome (RASA1 syndrome).


Vascular malformations may be divided into high or low flow and also by the major component vessel. Consequently there are capillary malformations (eg ‘stork bight’) , venous malformations, lymphatic malformations, arteriovenous malformations and arteriovenous fistulas. The first three are low flow malformations and the last two high flow malformations. There may be mixtures of the types of lesion.  These lesions may or may not progress but very rarely resolve by themselves.


Symptoms vary considerably with the type of malformation and the location. These can include pain, swelling, visible lesion, bleeding, ulceration and  overgrowth of a limb. Some vascular lesions can be diagnosed clinically but most will require some imaging. MRI is the most useful imaging for making an accurate diagnosis and for planning therapy. Although vascular lesions can often be identified or diagnosed on ultrasound/doppler this is rarely sufficient to plan therapy.

Venous malformation

Venous malformations are the most common vascular lesion encountered in adults. The most common presentations are pain, swelling or visible abnormal veins. Venous malformations have usually been present most of the patient’s life but may begin to grow or become symptomatic at any age. Growth may be noticed at puberty or during pregnancy. Growth of the venous malformation lesion is usually relatively slow.


Venous malformations can occur anywhere but are relatively common in the head and neck. They can cross any tissue planes with some visible on the skin but most lying deep to the skin. There may be associated overgrowth of local tissues or even of a whole limb.


In regards to treatment, surgery used to be the main treatment but nowadays the main treatment is sclerotherapy. Sclerotherapy involves direct injection of a substance (sclerosant) into the lesion to damage the lining of the component vessels to result in thrombosis and scarring of the vessels. This treatment usually involves multiple sessions. It will usually result in reduction in size of the lesion and improvement in pain. Initially however there is swelling and there may be some discomfort. Complications of sclerotherapy can include skin ulceration, nerve damage and DVT. The treatment usually doesn’t completely destroy the lesion but usually provides clinical control for a prolonged period of time.


A typical treatment involves a day only or overnight stay, usually with a general anaesthetic. Patients will experience swelling of the treated area, peaking in the first few days after treatment and decreasing over the subsequent weeks. Post operative discomfort is usually only mild. Multiple treatments with sclerotherapy are usually required except for the smallest of lesions.

Arteriovenous Malformation

Arteriovenous malformations (AVM) and arteriovenous fistulas (AVF) both involve high blood flow through abnormal arterial to venous connections. In AVM this is through a localised area of tangled, enlarged vessels called a nidus and in AVF there is usually only one or a few direct connecting vessels. These lesions tend to worsen, though at an unpredictable rate. The presentations include visible lesion, pain, ulceration, bleeding, overgrowth and pressure on nearby structures. Periods of growth often co-incide with puberty, pregnancy and local trauma.


Treatment may involve surgery, embolisation (blockage/damage to the involved vessels), laser (superficial lesions only) and radiation. Most treatment has been surgery in the past but increasingly embolisation is the main treatment. Embolisation has become much more effective since the use of liquid embolic materials (eg histoacryl glue, Onyx and alcohol). Embolisation will usually control the lesion with a minimally invasive approach. Combination of embolisation and later (less extensive) surgery is not uncommon.


All treatments often fail to completely eradicate the lesion but will usually give prolonged periods of clinical control. Complications of embolization include skin ulceration, nerve injury and  unintentional blockage of normal blood vessels.


A typical  peripheral AVM treatment would involve day or overnight hospital stay with  the procedure being performed under general anaesthetic. There will usually be swelling post embolisation, especially in the first week. There may also be some discomfort but this is usually fairly easily managed in the post-operative period by our anaesthetists.

Lymphatic Malformation

Lymphatic malformations are collections of abnormally large lymph vessels and mainly contain simple yellow fluid (lymph). These create cysts which can be large and few in number , multiple and small or some combination of these. There can also be overlying skin changes with a wart like appearance. These lesions mainly result in presentation due to the swelling which may vary in size over time. Lymphatic malformations will often enlarge with viral infections but may themselves become infected . Occasionally there is bleeding into the lymphatic malformation. The lesions may also cause problems because of pressure on nearby structures. 


Surgery and sclerotherapy are the main treatments for lymphatic malformation. The most appropriate treatment will depend on the size, location and type of lesion. Sclerotherapy is most effective in lesions with large cysts and where a surgical approach is likely to cause excess injury to surrounding tissues. Sclerotherapy treatment is becoming more important in the treatment of these lesions, especially with the newer sclerosant agents, such as Bleomycin. These newer agents are effective with reduced complications.