Arteriovenous malformations or AVMs are rare vascular malformations (abnormal tangles of blood vessels where direct connections form between arteries and veins) which disrupt natural blood flow. AVMs most commonly affect the central nervous system (brain and spinal cord) but can involve any organ. Those affecting the face, head or neck are often called extracranial arteriovenous malformations (AVMs)
. Although present at birth, AVMs may not be clinically evident until childhood or adolescence. Complications may include disfigurement, destruction of tissue, obstruction of vital structures, pain, bleeding, ulceration and rarely, cardiac overload. AVMs may be treated with surgery, embolization, or both. The goal of treatment is to control rather than cure the underlying problem. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.