Brain cysts are not tumors, so you can rest assured that brain cysts are actually membranous structures wrapped around cerebrospinal fluid, and there may be other substances inside, but they are definitely not tumors and are not classified as benign or malignant. With the gradual increase of the cyst, it will compress the normal brain tissue, causing headache, dizziness, nausea, vomiting, seizure, numbness and weakness of the limbs, speech dysfunction and a series of other symptoms, and compressing the endocrine glands, such as pituitary gland and pineal gland, causing endocrine function disorder, like the most common pituitary cyst, which may cause the disorder of gonadal hormone secretion and prolactin increase. The most common pituitary cysts may cause disorders of gonadal hormone secretion, increased prolactin, endocrine system and other related abnormalities, but they are not tumors and can be effectively treated.