###Human: What causes a swollen lymph node behind the ear? ###Assistant: Hi. It looks like you have a small benign lymph node. Lymph nodes do no harm and everyone has lots of them in their bodies. These flare up only when there is a little infection to fight in your surroundings. So there is not much to worry about, especially it is not cancer. Based on the photos and information you provided (attachment removed to protect patient identity), it may also be a benign lipoma which is a lump of fat slightly thicker and does not need anything to be done. Just leave it in place and it will go away on its own. Do not massage it. See a doctor if you experience pain or if it increases in size significantly. Take care.