Lymph nodes can become cancerous, and the common ones are lymphoma and metastatic cancer of lymph nodes in other parts of the body. Lymphoma is a primary malignant tumor of lymph nodes, which mainly manifests as painless enlargement of lymph nodes, and may present with systemic symptoms such as fever, itching, night sweating and emaciation. Some patients may have white blood cell count, thrombocytosis, rapid blood sedimentation, some patients may have leukemia-like reaction, and in advanced stage, patients may also have abnormal immune function. In addition, patients with malignant lymphoma may also have skin lesion-like changes, such as erythema multiforme, blisters, vesicles, etc. The lymph nodes are hard, with unclear borders, and some of them may be fused, which need to be further diagnosed through puncture biopsy and surgical incision. In addition, bone marrow smear also has certain diagnostic significance. For lymphoma patients, different treatments should be chosen according to the specific type of lymphoma, commonly used treatments include chemotherapy, radiotherapy and bone marrow transplantation. For patients with hypersplenism and enlarged spleen, surgical resection can be considered. As for lymph node metastatic cancer, first of all, the primary disease should be investigated, such as thyroid cancer, gastric cancer, lung cancer, stones, intestinal cancer and so on. Further treatment can be carried out through the primary diseases, such as radiotherapy and chemotherapy in oncology department, and oral levothyroxine sodium tablets and iodine 131 treatment, and so on.