Axillary lymph node 27mm suggests that there is lymph node enlargement, and the possible causes are: lymphoma, metastasis of malignant tumor, lymph node tuberculosis, inflammatory lymph node enlargement, etc. 1. Lymphoma: lymphoma is a malignant tumor originated from lymphatic tissues, most of the lymphomas take the first symptom of lymphoma enlargement on the surface of the body, which is mainly manifested as the painless and progressive enlargement of lymph nodes, and can be accompanied by low-grade fever, night sweats, itchy skin and other systemic symptoms. 2. Metastasis of malignant tumors: malignant tumors in other parts of the body can metastasize to axillary lymph nodes and cause lymph node enlargement, and breast cancer is the most common. In addition, axillary lymph node metastasis may also occur in sarcoma of upper limb, but it is relatively rare in clinic. 3. Tuberculosis of lymph nodes: invasion of lymph nodes by tuberculosis bacillus can also cause lymph node enlargement, and the enlarged lymph nodes can merge with each other to form a mass in the later stage. 4. Inflammatory lymph node enlargement: Infectious inflammation in neighboring areas can stimulate the axillary lymph nodes to appear reactive hyperplasia and enlargement. In addition to the above reasons, all kinds of infections, some autoimmune diseases, AIDS, etc. may appear axillary lymph node enlargement, it is recommended to go to the hospital as soon as possible, as soon as possible to determine the cause of the disease and then be treated accordingly.