Developmental Venous Anomaly (Brain)
A developmental venous anomaly (DVA), also called a venous angioma, is a congenital variation in the brain’s venous drainage system. It consists of a cluster of small veins arranged in a radial pattern that drain into a single enlarged collecting vein, creating a characteristic “caput medusae” or “umbrella” appearance on imaging. DVAs are the most common vascular malformation of the brain, found in approximately 2-3% of the population, and are typically discovered incidentally during brain imaging performed for other reasons.
What is it?
A developmental venous anomaly (DVA) is an anatomical variant where brain tissue is drained by an atypical arrangement of veins. During fetal development, when the normal venous drainage pathways fail to form properly, an alternative venous drainage system develops to compensate. This results in multiple small veins (medullary veins) converging in a spoke-like pattern into a single, larger collecting vein that drains into either a superficial cortical vein or a deep vein such as the internal cerebral vein.
DVAs can occur anywhere in the brain but are most commonly found in the frontal lobes and cerebellum. They represent a functionally important drainage pathway for normal brain tissue rather than a true malformation. The venous blood flow through a DVA is normal in direction and velocity, which distinguishes it from other vascular malformations. Most DVAs remain stable throughout a person’s lifetime and do not grow or change significantly over time.
Important to Know
DVAs are considered benign anatomical variants and almost never require treatment. The vast majority of people with DVAs experience no symptoms and live normal, healthy lives. However, there is a small association (5-30%) with cavernous malformations, which may rarely cause bleeding or seizures. For this reason, when a DVA is discovered, careful imaging review is performed to check for associated lesions. Patients are typically advised against surgical removal of isolated DVAs, as these structures represent the only venous drainage for the surrounding brain tissue—removing them could cause venous infarction and serious neurological damage. Recognition and proper diagnosis of DVAs by radiologists is important to avoid unnecessary anxiety or intervention.