Supratentorial arachnoid cyst mimicking a Meniere's disease attack

Arachnoid cysts (AC) often present with symptoms depending on their anatomical location within the skull; while supratentorial cysts grow causing relatively few symptoms, infratentorial ones may impair liquor circulation at the level of the fourth ventricle, giving rise to intracranial hypertension, or may stretch the complex nerve network in the cerebello-pontine angle. We report the singular clinical history of a 54-year-old male, who suddenly began to feel dizzy while sitting at his workplace, complaining of left tinnitus and aural fullness, in a classic clinical picture of Meniere's disease. The anomalous findings at otoneurological examination (markedly the left deviation at the Fukuda test) made a magnetic resonance image (MRI) scan mandatory and a huge AC was found in the left fronto-parietal lobe. The mass provoked an evident clockwise rotation of the brainstem that we suppose to be the cause of acoustico-facial bundle stretching explaining the vestibular symptomatology.