Objective improvement in adults with cerebellopontine angle arachnoid cysts after surgical treatment

Background Intracranial arachnoid cysts are extra-axial benign lesions mainly found in the middle cerebral fossa. Rare case series report various cranial nerve dysfunctions associated with cerebellopontine angle (CPA) cysts and there is no consensus with regard to their surgical management; some reports claiming that subjective improvement in adults with intracranial arachnoid cysts cannot justify surgical treatment. Methods This retrospective study included all 12 consecutive adult patients treated by microsurgical fenestration for symptomatic CPA arachnoid cysts between 2010 and 2019 and using a retrosigmoid approach. Demographic, clinical, surgical, and radiological data were collected from medical files. Results The main symptoms were audiovestibular in 9 patients (75%) complaining of dizziness and 6 patients (50%) with hearing loss. In addition, 3 patients (25%) reported tinnitus, 3 patients (25%) presented vasovagal syncope, and 1 patient (8.3%) reported facial pain. Surgery improved 5 patients (83%) with pre-operative hearing loss, 7 patients (78%) reporting dizziness, and all patients with vasovagal syncope. All of the patients recovered from at least one symptom. No recurrence was observed with a mean follow-up of 5.5 years. Conclusion Although most arachnoid cysts are asymptomatic, the CPA location may lead to cranial nerve impairments. Microsurgical fenestration seems to be a simple, safe, and effective technique.