Arachnoid cyst epidemiology and demographics

Arachnoid cysts occur in about 1.2% of the general population and are more frequently seen in men than in women.

• The prevalence of arachnoid cysts is estimated to be about 1200 in 100,000 of the general population;^[1]
• Arachnoid cysts are more prevalent in men;
• 50% occur in the middle cranial fossa;
• One third of the cases occur in the posterior fossa;
• Temporal cysts are 70% left-sided.^[1]

• Only 20% of these have symptoms, usually from secondary hydrocephalus.^[2]