What is an arachnoid cyst? Arachnoid cysts are congenital disorders that result from abnormal division of the arachnoid membrane during development. Most lesions become symptomatic in early childhood. The clinical presentation depends on the location of the cyst. There are often large lesions with mild symptoms. Typical manifestations 1. symptoms of increased intracranial pressure: headache, nausea and vomiting; 2. epilepsy; 3. sudden deterioration; 4. skull expansion; 5. local symptoms/signs due to occupational effects; 6. incidental findings during treatment of unrelated diseases. The diagnosis is usually confirmed by CT or MRI. Treatment Arachnoid cysts without occupational effects or symptoms. No treatment is required regardless of size or location. Surgical treatment options include syringe aspiration or drill hole drainage, craniotomy with excision of the cyst wall, cranial drilling with endoscopic cyst penetration, and cyst shunt to the abdominal cavity. Of these, cyst abdominal shunt using a low-pressure tube shunt into the abdominal cavity is the best method.