Polymorphic Clinical Presentation of Cerebellar Arachnoid Cyst: A Case Report. Etiopathogenetic Theory and Review of the Literature

Arachnoid cysts (AC) are developmental collections of cerebrospinal fluid covered by layers of arachnoidal epithelium and are usually located in the middle cranial fossa. Localizations in the posterior fossa are uncommon and generally remain asymptomatic or cause vague and non-specific symptoms. We describe the unusual case of a patient with an AC suffering from recurrent polymorphic vertigo with atypical nistagmus and transient sensorineural hearing loss. The clinical-diagnostic features are discussed, etiopathogenic theories are proposed and a review of the literature on posterior cranial fossa AC is reported.