Arachnoid cysts are the benign cysts in the cerebrospinal axis. These cysts usually occur in association with arachnoid cisterns. These cysts are congenital and diagnosed accidentally. Some time they are formed due to surgery and infections. The symptoms may include headache, bulging, l hypertension, visual loss, and seizures. If this cyst is not causing problem then there is no need of surgery. Even large size of these cysts does not cause problems.