Swollen left supraclavicular lymph nodes are not necessarily cancerous, but can also be caused by other reasons, which need to be analyzed on a case-by-case basis. Left supraclavicular lymph node is a very meaningful characteristic clinical manifestation. If a patient has enlarged lymph nodes along with weight loss, weakness, wasting and other cachectic manifestations, it usually indicates a higher possibility of tumor, such as gastric tumor, breast tumor and so on. Once the patient is diagnosed, it means that the tumor is in advanced stage and the effect of treatment is poor. Even if the primary lesion is surgically removed and chemotherapy is used, complete cure cannot be achieved. However, if there is only fever and pressure pain in lymph nodes without other clinical symptoms, it may also be caused by common lymph node inflammation. In addition, lymph node enlargement can be produced by lymphatic tuberculosis or mosquito bites or local skin allergy. Therefore, when a patient finds a left clavicular lymph node, he or she must go to the general surgery department of a hospital in time to perform abdominal CT, chest CT and gastroscopy to find the primary lesion, and if necessary, the enlarged lymph node can be removed or puncture biopsy sent to pathology for further clear diagnosis.