Venous Malformations

Know the Facts

Venous malformations range from simple to complex. Malformations also can involve lymph vessels (lymphatic malformations) or arteries connecting directly to veins without capillaries in between (arteriovenous malformations).


Venous malformations are mostly benign but some may progress leading to symptoms. They may cause pain or a lump under the skin. There may be an overlying birthmark on the skin. Skin lesions may cause bleeding or lymph fluid leaking. Pulmonary arteriovenous malformations (PAVM) shunt blood from the right side of the heart to the left without obtaining oxygen from the lungs, leading to shortness of breath, fatigue and the danger of clots causing strokes.


Some Venous malformations are present at birth; others are acquired. Venous and lymphatic malformations may be associated with a syndrome called Klippel-Trenaunay Syndrome. Congenital Venous malformations are rare.


Diagnosis and treatment of more complex venous malformations can be confusing. They are evaluated to determine what parts of the body may be affected, and a treatment plan, often involving multidisciplinary specialists, is developed. 


Venous malformations may become large over time and grow after puberty, trauma, or an infection. Combined vascular malformations are complex, involving more than one type malformation. These can be associated with overgrowth of bone and soft tissues, usually in a limb.

Treatment Options

Surgery or embolization may be used to successfully treat venous malformations.