The incidence of brain tumors is relatively low compared to tumors in other parts of the body, but there are many types of brain tumors. Generally speaking, malignant tumors in the brain grow faster and can grow to a larger size within months or even weeks, while benign tumors grow relatively slowly and often take several years to grow to a larger size in the brain. So purely in terms of growth time, it seems that malignant tumors are more likely to grow to a relatively large size quickly. However, the process of brain tumor growth is also a process of tumor interaction with brain tissue and human body. Whether benign or malignant tumors, they may grow to a large size before they are discovered. Mr. Song once had his left eye removed due to an eye disease when he was a child, and then he recovered quite well until he grew up. However, in the last three to four months, he had headaches and blurred vision, and as his symptoms gradually worsened, he discovered a huge tumor in his brain through MRI at a local hospital, with a diameter of 8cm. The headache could only be relieved briefly by high doses of dehydration drugs. Fortunately, Mr. Song’s tumor was a benign meningioma. Therefore, a large size of brain tumor is not necessarily a malignant tumor. The severity of symptoms caused by brain tumor is closely related to the growth rate and growth site of the tumor. When the tumor grows particularly fast, due to the limited volume of the cranial cavity where the brain is located, the brain tissue is too late to adapt and compensate, and the tumor will cause more obvious symptoms when it grows to a certain extent. When the tumor is located near the brain nerves or functional areas, the tumor will soon compress these structures during the growth process to cause corresponding symptoms of functional deficiency or localization signs, or when the tumor is located near the cerebrospinal fluid circulation pathway, it will soon block the cerebrospinal fluid circulation pathway during the growth process to cause hydrocephalus symptoms, the tumor may be detected when it is relatively small. And when the tumor grows in areas of the brain far away from important functional areas and cerebrospinal fluid circulation pathways, the tumor can grow slowly without causing obvious symptoms until the tumor becomes huge in size beyond the body’s ability to adapt and compensate, then it will begin to cause obvious symptoms.