Nearly half of adult patients and about one-third of pediatric patients have arachnoid cysts located in the lateral cerebral fissure. The size of the cysts varies. Bilateral arachnoid cysts are uncommon. Although lateral fissure cysts can present with symptoms at any age, they are more common in children and adolescents. The male to female ratio is 3:1. Involvement of the left hemisphere is more common than the right. Unilateral headache is most common, with pain in the supraorbital or temporal region being the most typical. The next common symptom that can occur in more than 1/4 of patients is various types of seizures. Some adolescent patients can have severe headaches while chewing or headaches that worsen during exercise and heavy physical work. Other symptoms include mild proptosis, nausea, vomiting, and mild contralateral hand weakness or light paralysis. Patients with arachnoid cysts are less likely to have developmental delays or learning difficulties. Giant lateral cysts in young children can lead to macrocrania and separation of the bony sutures. In many patients, localized elevation of the temporal bone is seen, and cranial radiographs show thinning of the temporal bone scales and displacement of the pterygoid wings. ct shows unenhanced cerebrospinal fluid collections at the medial temporal apices of the lateral fissure. galassi et al. divided the lateral fissure cysts into 3 subtypes. type I cysts have a bean-like biconvex shape at the temporal apices and are rarely associated with remodeling of the middle cranial fossa. these cysts may traffic freely with cerebrospinal fluid from the subarachnoid space. Type II cysts are massive quadrilateral cysts with some occupying effect on adjacent nerves and lone star structures. There is delayed absorption of the contrast agent within the cyst on brain pool imaging. type III cysts are giant and round, causing severe compression of the insula cap and insula cortex, deforming the lateral ventricles and shifting the midline. These cysts do not traffic with cerebrospinal fluid in the subarachnoid space. It remains unclear whether type I cysts can progressively increase in size to form a large occupying injury. Treatment decisions need to be made with a thorough consideration of the clinical presentation and neuroimaging findings. Typical type I cysts do not require surgical treatment in the absence of clinical symptoms. Conservative treatment with annual neuroimaging follow-up for 1-2 years is recommended for these patients; in pediatric patients, neuroimaging follow-up should be performed every 6 months for 18 months. Large and symptomatic type III cysts require surgical treatment in both adult and pediatric patients. Surgical treatment should also be performed if patients with type II cysts, which are an excessive type of cyst, present with severe severe or symptoms that are not compatible with the size of the cyst. Choosing the appropriate drainage technique for patients with clinical symptoms can be a challenge. Cystoperitoneal (CP) shunts have many advantages, are commonly used in patients of all age groups, and allow rapid return of the displaced cortex and midline after shunting.Complications of CP shunts include intracapsular hemorrhage, shunt infection, overshunting, hypocranial pressure headache and shunt failure, and re-expansion of the cyst. In contrast to CP shunts, the cyst wall can be removed craniotomically and the cyst fluid drained into the basal pool, but the tight adhesions of the cyst wall to brain tissue and blood vessels may limit complete removal of the cyst wall, with a cyst reoccurrence rate approaching 25% in some cases. Excellent outcomes have been reported for endoscopic arachnoid cyst openings, but there is a possibility of complications such as bleeding and infection, and there are no large case reports on the probability of cyst recurrence, so further observations are needed.