Petrous apex's dural arteriovenous fistula (DAVF) mimicking a pineal region tumour: a rare cause of Hakim triad.

A dural arteriovenous fistula (DAVF) is a dural-based shunt between meningeal arteries and meningeal veins, sinuses and/or cortical veins; they have been classified and named according to the location and the flow pattern. Petrous apex DAVFs are located where the petrosal vein penetrates the dura mater into the superior petrosal sinus; there are only few cases reported in the literature, they can show an aggressive behaviour (subarachnoid haemorrhage, severe brainstem oedema) with a high mortality rate. The described case is, to the best of our knowledge, the first case of a DAVF presenting with symptoms mimicking idiopathic normal pressure hydrocephalus. After worsening of gait impairment, memory loss and urinary incontinence an urgent CT of the brain showed hydrocephalus and a hyperdense mass in the pineal region mimicking a pineal tumour; an emergent digital subtraction angiogram showed a left petrous apex Borden type III DAVF. A transvenous embolisation was performed obtaining a complete obliteration.