✓ Complex developmental venous anomalies (DVAs) represent variations of normal cerebral venous drainage and consist of dilation of the superficial and/or deep venous system. These rare anomalies can occur unilaterally or bilaterally, supratentorially or infratentorially, focally or they can affect the entire hemisphere. Some DVAs are associated with cervicofacial venous malformations or facial lymphatic malformations. Anomalies of this type are generally clinically silent, and cerebral dysfunction is usually absent. Symptoms, when they occur, are most commonly headache or mild seizure disorders. The angiographic findings are striking, with well-formed but enlarged transcerebral medullary and deep and/or superficial cortical veins. Opacification of these venous structures occurs within the same time frame as a normal angiographic venous phase.
The authors report the case of a 33-year-old man in whom a large inoperable arteriovenous malformation had been previously diagnosed and who presented with seizures. Repeated magnetic resonance imaging and angiography demonstrated abnormally dilated transcerebral, superficial, and deep venous structures involving the entire right hemisphere with no identifiable nidus. Additionally, multiple bilateral benign facial hemangiomas were present in this patient.
It is important to recognize this rare venous appearance as a developmental variant and not mistake it for an arteriovenous malformation or a partially thrombosed vein of Galen malformation. Because these venous anomalies are extreme variants of the normal venous system, hemorrhage rarely, if ever, occurs and the patient can be reassured that no interventional or surgical therapy is necessary or warranted.