Benign brain tumors can cause hydrocephalus because hydrocephalus does not strictly distinguish whether it is caused by a benign brain tumor or a malignant one. As long as the normal circulation of cerebrospinal fluid is disrupted, hydrocephalus may develop. For example, choroidal papilloma is a benign tumor, which produces excessive cerebrospinal fluid, which is not fully absorbed and eventually forms hydrocephalus. Another example is meningioma or acoustic neuroma, or tumors in the pontocerebellar horn area or part of the cerebellum, which can compress and block the normal cerebrospinal fluid circulation pathway, such as the fourth ventricle, and can also lead to the formation of hydrocephalus. Therefore, it is necessary to distinguish what kind of factors cause hydrocephalus, not mainly distinguish whether it is benign or malignant, but it is necessary to be clear, and early detection and early treatment are more favorable.