Lymphocele mainly refers to the enlargement of lymph nodes, which leads to its occurrence for more reasons, such as infectious diseases, malignant tumors, immune system diseases, tissue proliferative diseases, and other diseases. 1. Infectious diseases: i.e. diseases caused by multiple pathogen infections, including viral infections, such as herpes virus, varicella zoster virus, rubella virus, etc.; bacterial infections, such as Mycobacterium tuberculosis, streptococcus, etc.; fungal infections, such as coccidioidomycosis, etc.; spirochetes, chlamydia, parasitic infections and so on. 2. Malignant tumors: including hematologic tumors, such as leukemia, malignant lymphoma, etc.; or lymph node metastasis of malignant tumors in other systems, such as lung cancer, breast cancer, gastrointestinal tract tumors, etc. 3. Immune system diseases: mainly autoimmune system diseases, such as rheumatoid arthritis, systemic lupus erythematosus, desiccation syndrome, mixed connective tissue disease, dermatomyositis, etc., which may lead to lymph node enlargement. 4. Tissue proliferative diseases: mainly some lipid deposition diseases, such as Niemann-Pick disease, Gosheimer’s disease and so on. 5. Other diseases: including acute lymphadenitis, nodular disease, lymphomatoid granulomatosis, inflammatory pseudotumor of lymph nodes, etc. It is recommended that after the appearance of enlarged lymph nodes, timely consultation should be made to clarify the specific cause of the disease, and active treatment should be carried out.