Lymph nodes of 2cm may be caused by lymphadenitis, lymphoma, or diseases of neighboring organs. 1. Lymphadenitis: Inflammatory reaction of lymph nodes caused by infection of external pathogenic bacteria will result in enlarged, swollen and painful lymph nodes, which may appear as 2cm lymph nodes. 2. Lymphoma: Lymphoma is a malignant tumor of the immune system. It can also cause 2cm lymph nodes. 3. Diseases of neighboring organs: For example, if there are enlarged lymph nodes under the jaw, it is possible that the enlarged lymph nodes are caused by diseases of neighboring organs, such as thyroid diseases, breast diseases, throat diseases, etc. It is recommended to go to the regular hospital for examination first. It is recommended to go to the regular hospital for examination, to clarify the cause of the disease, and take appropriate treatment measures according to the doctor’s instructions.