Intracranial arachnoid cysts: Review of natural history and proposed treatment algorithm

BACKGROUND: With a prevalence of 1.4%, intracranial arachnoid cysts are a frequent incidental finding on MRI and CT. Whilst most cysts are benign in the long-term, clinical practice, and imaging frequency does not necessarily reflect this. METHODS: A literature review was conducted searching the Medline database with MESH terms. This literature was condensed into an article, edited by a consultant neurosurgeon. This was further condensed, presented to the neurosurgery department at Princess Alexandra Hospital for final feedback and editing. RESULTS: This review advises that asymptomatic patients with typical cysts have a low risk of cyst growth and development of new symptomatology, thus do not require surveillance or intervention. The minority of symptomatic patients or those with cysts in sensitive areas may require referral to a neurosurgeon for clinical follow-up or intervention. CONCLUSION: Greater than 94% of patients are asymptomatic, practitioners can be confident in reassuring patients of the benign nature of a potentially worrying finding. Recognizing the small number of symptomatic patients and those with cysts in areas sensitive to causing hydrocephalus is where GP decision making in conjunction with specialty input is of highest yield.