Arteriovenous malformations (AVMs) are vascular anomalies that typically present in the head / neck area that are often present at birth (40%). They are considered fast-flow anomalies, compared to venous malformations, which are slow flow.

AVMs are most often confused with port-wine stains or an involuting hemangioma. AVMs may worsen over time, causing disfigurement, pain, hemorrhage, and possibly death. It is uncommon for there to be extracutaneous findings such as heart failure in the neonate.

AVMs are sometimes associated with a somatic mutation in the KRAS gene.