In clinical practice, the decision to operate on an arachnoid cyst is not based on size, but rather on the patient’s clinical symptoms and the pressure on the brain. In some cases, if the brain atrophy is very pronounced and the arachnoid cyst is very large, but the patient does not have any clinical symptoms, surgery is not recommended as it carries certain risks and may cause adverse reactions in the patient. If the patient’s arachnoid cyst increases rapidly within a short period of time, severely compressing the brain tissue and creating very serious clinical symptoms or even causing life-threatening effects. In this case, surgical treatment is necessary, either craniotomy or minimally invasive puncture surgery. Therefore, it is important to evaluate the patient’s actual situation in order to be the most accurate, otherwise many times it is easy to miss and misdiagnose.