Catch me if you can: disappearing and reappearing posterior fossa dural arteriovenous malformation.

Agnoletto, Guilherme J; Hoover, Jason M; Monteiro, Andre; Hanel, Ricardo A

We report an unusual case of a dural arteriovenous fistula (dAVF) presenting as acute neck pain and quadripareis in a 55-year-old previously healthy man. Imaging was suspicious for cervicomedullary venous thrombosis and angiography failed to show evidence of arteriovenous malformation or dAVF. The patient was started on warfarin for a presumed cervicomedullary venous thrombosis and there was a significant clinical improvement. However, 3 weeks later, the symptoms recurred and repeat angiography revealed a dAVF fed by a posterior branch of the left middle meningeal artery draining into the posterior fossa vein. We postulated that warfarin caused recanalisation of the previously thrombosed venous pouch allowing for angiographic discovery and treatment of the dAVF. The dAVF was embolised with onyx resulting in the complete obliteration of the dAVF and symptomatic improvement. Although rare, some dAVF can be concealed or disappear on angiography due to thrombosis of the draining vein and warfarin can lead to recanalisation.