Venous malformations - cutaneous

Venous malformations (VMs) are sporadic, caused by malformed dilated veins, and can affect any tissue or organ. They appear as skin-coloured, blue or purple swellings, often with prominent veins near the skin surface. VMs are always present at birth, although may not become clinically apparent until later. They may vary in size from small to occasionally involving a whole limb. Unlike infantile haemangiomas, they grow in proportion to the child's general growth.

This chapter is set out as follows:

• Venous malformations are rare with have an incidence estimated around 1:10 000
• Males and females are equally affected

• Grow proportionately with the individual
• They never regress spontaneously
• Although often asymptomatic, they can be painful, cause bleeding and/or functional impairment - on the extremities can cause muscle weakness
• Pulmonary thromboembolism has been reported in some patients with extensive VMs of the extremities

• Mainly solitary, <1% are multifocal
• Variable size, from small blebs to large, bluish lesions
• There is no thrill or bruit, and the malformation is not warmer than non‐lesional areas
  
• Associations - VMs can be associated with various conditions such as Maffucci syndrome, characterised by enchondromas, bone deformities, and venous malformations
  
• The Blue Rubber Bleb Naevus syndrome is a rare syndrome comprising of multiple venous malformations of the skin, gastrointestinal tract and other organs (refer to the related chapter for more information)
• Glomulovenous malformation (GVMs) can have a similar appearance to the above, but differ in that they are inherited, lesions tend to be painless unless knocked or during an extreme change in temperature, and they do not involve internal organs (refer to the related chapter for more information)

• Doppler ultrasound (sometimes with MRI) is the best examination to confirm the vascular nature of the lesion (slow flow) and to identify the anatomy of the draining vessels 
• Larger and more extensive lesions can be associated with coagulation abnormalities 

Prognosis

• Lesions never regress spontaneously
• Aesthetic and functional impairment worsen with time because of expansion or bleeding
• Depending on location and size, they can occasionally be life‐threatening

Management

• Patients require referring to Secondary Care, where a multidisciplinary approach is required
• Treatment strategies depend on the type of malformation and may include any of: tailored compression garments, aspirin, low‐molecular‐weight heparin if d‐dimer levels elevated, sclerotherapy, surgical resection, and laser therapy