Lymphoma is a group of malignant tumours originating from lymph nodes or other lymphoid tissues, caused by the uncontrolled proliferation of lymphocytes that mutate and accumulate in different parts of the body, and manifests itself mainly as painless enlargement of lymph nodes. Patients often unknowingly notice swollen lymph nodes on their body without any sensation, and they may feel tough to the touch, but they may also feel less mobile, so they should be aware of the possibility of lymph node tumours.