Intracranial tumors are divided into primary and secondary. Primary brain tumors originate from various intracranial tissue components such as meninges, brain tissue, cranial nerves, cerebral blood vessels, pituitary glands and embryonic remnants. In secondary cases, malignant tumors from other parts of the body, such as lung, uterus, breast, gastrointestinal tract, liver, etc., metastasize to the brain, or malignant tumors from neighboring organs invade into the skull from the skull base.