Lymph node lesions can be detected by ultrasound. A normal lymph node is oval or bean-shaped, with one end protruding and one end depressed, and the depressed end is called the lymph node gate, with a clear demarcation between the cortex and the medulla inside the lymph node. If the lymph nodes become diseased, such as enlargement or metastasis, the lymph nodes will change from oval to round, the lymph node gate will disappear, the cortical and medullary divisions inside the lymph nodes are not clear, and there may be abnormal blood flow signals around the lymph nodes. If necessary, the lymph nodes can be completely removed and sent to pathological examination for further clarification. If tumor cells can be found inside the lymph nodes, it can prove that the lymph nodes are caused by tumor metastasis.