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The definition and classification of vascular anomalies is confusing. There are two main types.
Haemangiomas are acquired lesions that affect infants and enlarge to cause disfiguring lesions. Fortunately they almost always regress completely without treatment. The term haemangioma is often used incorrectly to include vascular malformations.
True vascular malformations are congenital abnormalities of blood vessels. They are rare and the cause is unknown. They are subdivided into:
High flow (due to abnormal connections between arteries and veins)
Low Flow lesions subdivided further into:
Capillary
Venous
Lymphatic
Mixed
How do vascular malformations progress?
Vascular malformations are present at birth though may grow markedly in response to puberty, pregnancy, trauma or a misguided attempt at excision.
Symptoms and signs vary widely. A skin component may be easily visible but this may represent only a small part of a much larger abnormality. Some lesions are painful. Others cause extreme deformity (everyone is familiar with the Elephant Man, he had an extensive vascular malformation). High flow lesions may have a bruit (a whooshy noise audible through a stethoscope). Lymphatic malformations may weep and ulcerate.
The differential diagnosis includes soft tissue tumours and it is vital not to confuse a malignant soft tissue tumour with a benign vascular malformation. Arterio-venous fistulae resulting from trauma may mimic a high flow malformation.
How are vascular malformations diagnosed and assessed?
Doppler ultrasound, CT scanning, MRI scanning and angiography may all be helpful in establishing the nature and extent of the malformation.
Treatment of vascular malformations
Treatment is not always necessary; many vascular malformations can be safely left alone. Treatment may involve coil embolisation, various forms of sclerotherapy injections, laser ablation or surgical excision.