What is a vascular malformation?
A vascular malformation is a structural error in the development of blood vessels. It is not a tumour formed by cell proliferation; the vascular network itself has been built incorrectly from the start.
Three features define the diagnosis:
- It is present from birth. Some are small or pale and go unnoticed in the first years.
- It grows with the child. It enlarges in proportion as the body grows.
- It does not regress on its own. Waiting for it to shrink over time does not work.
Puberty, pregnancy, trauma or infection can cause an existing malformation to become suddenly prominent. This does not mean the lesion is “new”; the structure that was already there has expanded.
Types
Vascular malformations fall into two main groups according to the speed of blood flow within them. This distinction determines the method of treatment directly.
| Group | Type | Typical finding |
|---|---|---|
| Slow-flow | Capillary malformation | A flat pink-to-purple discolouration of the skin (port-wine stain); not raised |
| Venous malformation | Soft, bluish swelling; becomes prominent when the limb hangs down or on straining | |
| Lymphatic malformation | Sac-like swellings containing clear fluid; may enlarge suddenly with infection | |
| Fast-flow | Arteriovenous malformation / fistula | Increased warmth, a palpable pulse; discolouration of the skin and progressive growth |
| Combined | Forms in which more than one type occurs together | Often accompanied by thickening of a limb or a difference in length |
Fast-flow malformations are the more demanding group; planning and follow-up differ from those of slow-flow lesions.
Why does an accurate diagnosis matter so much?
Any congenital vascular mark tends, out of habit, to be called a “hemangioma”. Yet a hemangioma is a tumour that grows and then regresses, whereas a malformation does not regress.
The practical consequence of that confusion is this: a child with a malformation may be observed for years on the assumption that “it will resolve in time”. Over that period the lesion grows, extends into surrounding tissue and becomes harder to treat. Naming it correctly is the first step of treatment.
Signs
The findings vary with the type and the site:
- Permanent discolouration of the skin
- Soft swelling that changes in size with posture, crying or exertion
- Pain, a sensation of tightness and firm areas within the swelling (from clotting in venous malformations)
- Recurrent infection and sudden increases in size (in lymphatic malformations)
- Warmth, a pulsing sensation, bleeding (in fast-flow lesions)
- A difference in the thickness or length of a limb
- Depending on the site, pressure effects on chewing, speech, vision or breathing
Diagnosis
Examination is often enough to distinguish the type; to plan treatment, however, the depth, margins and flow characteristics of the lesion are established by imaging.
- Colour Doppler ultrasound. Shows whether the flow is fast or slow; this is the first-line investigation.
- MRI and MR angiography. Reveal the relationship of the lesion to muscle, bone and nerves; this is the basis of surgical planning.
- Angiography. Used in fast-flow lesions to map the feeding vessels, and allows treatment in the same session.
- Genetic assessment. Requested in cases where a syndromic pattern is suspected.
Treatment
There is no single standard treatment for vascular malformations. The plan is built according to the type, site and size, the age of the patient and the symptoms the lesion causes. Treatment is often delivered in stages and planned together with interventional radiology.
- Intralesional medication. In venous and lymphatic malformations, closing the vascular spaces with an agent injected into the lesion is a widely used method. Several sessions are usually required.
- Embolisation. Occlusion of the feeding vessels through a catheter in fast-flow lesions. It is also used before surgery to reduce bleeding.
- Laser. Effective in lightening the colour of superficial capillary malformations; it requires sessions and the result varies between individuals.
- Surgical excision. Used alone in lesions with defined margins, and in extensive lesions after they have been reduced by the methods above.
- Supportive measures. Compression garments, pain management and early treatment of infection in lymphatic lesions form part of follow-up.
Setting realistic expectations matters: in some malformations the aim is not to remove the lesion entirely but to bring its growth under control and relieve the symptoms. Re-expansion can occur after treatment, which is why follow-up continues.
Conditions seen as part of a syndrome
Some vascular malformations form part of syndromes that involve other organ systems as well. Where the skin finding is accompanied by findings in the eye, brain, skeleton or limb development, assessment is multidisciplinary and follow-up is long-term.
For this reason, further investigation is requested in lesions that are extensive, that run along a limb, or that involve particular regions of the face as a whole.
Assessment
The most common mistake in vascular malformations is a delayed diagnosis. Once the type of lesion is clear, the treatment options become clear as well.
If you or your child has a vascular lesion that has been present since birth, that has grown along with the child, or that changes in size with posture, you are welcome to book an appointment for assessment. Bringing any previous imaging results will speed up planning.