Although the association of developmental venous anomalies (DVAs) with cavernous malformations is well documented, the association with arteriovenous malformations (AVM) is unusual. The aim is herein to report an additional case and to review the concepts associated to these mixed malformations in order to guide patient management.

A case of AVM associated with a DVA was identified and a literature review was performed according to PRISMA guidelines.

In an 18-year-old man presenting with sub-acute headache but with a normal neurological examination, the MRI-scan showed a right occipital DVA associated with hemosiderin spots evocative of earlier asymptomatic bleedings. The Digital Subtraction Angiography revealed a right parieto-occipital Spetzler-Martin Grade III AVM, fed by branches from the right middle and posterior cerebral arteries, with a superficial drainage flowing into a DVA that then joined the superior sagittal sinus. Multistep embolization was performed, leading to a partial reduction of the nidus, but preserving the DVA permeability. After a six-year follow-up. bleeding did not recur and the MRI aspect of the malformation was perfectly stable.

The co-occurrence of a DVA and an AVM is rare but has a higher bleeding risk than AVM alone (69% vs 38%) and must consequently be suspected when a DVA is revealed by a haemorrhage, in the absence of associated cavernoma. These mixed malformations represent a therapeutic challenge which has to be tailored to the venous anatomy and to the malformation Spetzler-Martin grade. DVA permeability should be preserved to avoid deleterious venous infarction.