The term "benign" refers to a condition, tumor, or growth that is NOT cancerous. This means that it does not spread to other parts of the body or destroy nearby tissue. Benign tumors usually grow slowly.
In general, a benign tumor or condition is not harmful. However, this is not always the case. If a benign tumor is big enough, it can press on nearby blood vessels, nerves, or organs, or otherwise cause problems. This is especially true for benign brain tumors.