Axillary lymph nodes are generally enlarged lymph nodes in the armpit and can be caused by two general factors. First, caused by inflammation in the body, lymph nodes play an important role in the anti-inflammatory process of the body. When the inflammation in the body is more serious, the immune system needs to be activated, which includes lymph nodes, and their enlargement can improve the immunity of the person. Secondly, metastasis of cancer can also lead to enlargement of lymph nodes, because the immune system is an important way in the process of metastasis of cancer cells, and the lymph in other places can also appear enlarged due to the erosion of cancer cells. To distinguish the above two cases, we need to conduct further examinations, such as blood tests to check the number of white blood cells, or ultrasound-guided puncture of the swollen lymph nodes, and then send them for pathological examination, so as to clearly diagnose the causes of swollen lymph nodes. If the swollen lymph nodes are caused by cancer metastasis, pathological examination can also guide the next step of treatment.