[Case Report of Cerebellar Vermis Arteriovenous Malformation Presenting with Hydrocephalus due to Aqueductal Stenosis].

A 56-year-old man complained of gait disturbance and confused thinking. Magnetic resonance imaging(MRI)revealed an arteriovenous malformation(AVM)of the cerebellar vermis(Spetzler-Martin grade IV)causing hydrocephalus. One dilated precentral cerebellar vein was compressing the aqueduct. After feeder embolization over 3 sessions using N-butyl cyanoacrylate(NBCA), the nidus was reduced to one-third in size. However, symptoms remained unimproved, and endoscopic third ventriculostomy(ETV)was performed. The third ventricle showed thinning of the floor, with a fenestration in part of the floor. Radiological findings and clinical symptoms improved, and the patient returned home after rehabilitation. The condition of the patient remained stable as of six months later. On angiography, the draining vein showed a pressure of 20 mmHg with no change in the residual AVM. Embolization alone achieved a reduction in nidus volume, but could not reduce venous pressure, and combination therapy including ETV proved necessary. Cases with hydrocephalus due to aqueductal stenosis by AVM are extremely rare. This pathology is discussed with reference to the literature.