is a growth of cells in the brain or near it. Brain tumors can happen in or near the brain tissue. Nearby areas where brain tumors can happen include nerves, the pituitary gland, the pineal gland and the membranes that cover the surface of the brain. If Brain tumors begins in the brain; These are called primary brain tumors. Sometimes, cancer spreads to the brain from other parts of the body; These tumors are secondary brain tumors, also called metastatic brain tumors