Enlargement of retroperitoneal lymph nodes may be caused by inflammation, tuberculosis, tumor and other factors. 1. Inflammation: when the abdominal organs and peritoneum are infected by bacteria, viruses and other pathogenic microorganisms, an inflammatory reaction will occur, which will stimulate the nearby lymph nodes to hyperplasia and enlargement. Such as chronic colitis, nephritis, chronic gastritis, chronic cholecystitis and so on. 2. Tuberculosis: tuberculosis is usually caused by Mycobacterium tuberculosis infection, which can invade the intestines and peritoneum, and the symptoms of enlarged retroperitoneal lymph nodes may appear after infection. 3. Tumor: when there is tumor lesion in peritoneum or abdominal organs, it will be transferred to lymph nodes through lymph, resulting in lymph node enlargement. For example, stomach cancer, intestinal cancer, kidney cancer, liver cancer and so on. When the symptoms of enlarged retroperitoneal lymph nodes appear, one should go to the hospital in time, and under the guidance of physicians, carry out relevant examinations and identify the cause of the disease and then carry out relevant treatments.