Benign (Non-Malignant): A benign tumor is one that lacks the malignant properties of a cancer. It does not grow in an unlimited, aggressive manner and does not metastasize (travel to other organs). Although many brain tumor types are considered histologically benign such as pituitary adenomas, chordomas, craniopharyngiomas and meningiomas, they can still be locally invasive, cause serious disability and be difficult to control with surgery alone.