Venous malformations, or developmental venous anomalies, represent variant development of the cerebral veins. A venous malformation is usually composed of a single dilated, tortuous collecting vein with radially-oriented subcortical medullary veins. While venous malformations of the brain are quite common (the estimated incidence in the general population is 0.5%), they are usually benign and asymptomatic.
Symptoms are unusual, and treatment of venous malformations of the brain is rarely necessary. In the unusual case of hemorrhage associated with a venous malformation, it is usually secondary to a nearby cavernous malformation.