A combined vascular malformation involves two or more types of blood and / or lymphatic vessel defects. Any of the four types of lesions (capillary, venous, lymphatic, or arteriovenous) may be combined (illustration 1).
Most combined malformations involve arms or legs. Any area of the body may be involved. The abnormal vessels develop early in pregnancy. They are thought to be caused by incorrect formation of the circulatory system (blood vessels and lymphatic channels) in a particular area of the body.
A genetic cause has been found for some combined malformations. They may or may not be inherited.
Diagnosis of Combined Vascular Malformations
Combined lesions are usually able to be diagnosed by a patient’s history and physical examination. Larger combined lesions may be seen on prenatal ultrasound. Radiologic imaging such as ultrasonography, magnetic resonance imaging (MRI), or computed tomography (CT or CAT scan) may be needed to confirm diagnosis or to see the extent of the malformation. Plain X-rays allow doctors to see how the lesion is affecting bone growth.
Complications vary with the vessels involved in the malformation. More complications tend to occur when the malformation is large and when more types of vessels are involved. Lymphatic blebs (blister-like lesions) may leak lymphatic fluid or bleed. Abnormal lymphatic vessels increase the risk of infection in the area of the malformation. Abnormal veins may cause pain, swelling, clotting problems, or heaviness of the affected limb.
In combined lesions with an arteriovenous malformation, the major concerns are due to the abnormal flow of blood from arteries into veins. Normally, blood does not flow directly from an artery to a vein. This may cause pain, skin breakdown, tissue loss and/or overgrowth the affected area on the body. Combined lesions with arteriovenous malformation may lead to heart failure.
Treatment of Combined Vascular Malformations
Treatment for combined malformations depends on what types of abnormal vessels are involved. All patients require evaluation by a multidisciplinary team with expertise in management of vascular malformations. Treatment approaches require different types of specialists to work together.
Many malformations are treated with compression garments. Complex lesions may require medications, sclerotherapy, embolization, and / or surgical excision. For combined malformations, treatment plans often combine a variety of these approaches over time.
For more information on these approaches, refer to the information on capillary, venous, lymphatic, and arteriovenous malformations.