Which kind of tumor grows slowly and is surrounded by membranes that prevent it from spreading from the original site?

The tumors may be either benign (not cancer) or malignant (cancer): Benign brain and spinal cord tumors grow and press on nearby areas of the brain. They rarely spread into other tissues and may recur (come back). Malignant brain and spinal cord tumors are likely to grow quickly and spread into other brain tissue.