Retroperitoneal lymph node enlargement usually refers to the enlargement of lymph nodes caused by inflammatory diseases or malignant tumors in the abdominal cavity, which requires prompt medical treatment once discovered. Retroperitoneal lymph node enlargement is often seen in inflammatory diseases in the abdominal cavity and metastatic malignant tumors in the abdominal cavity. 1. Inflammatory diseases in the abdominal cavity are more common, such as mesenteric lymphadenitis, acute cholecystitis, acute appendicitis or acute peritonitis, which can cause some degree of enlargement of retroperitoneal lymph nodes. Anti-inflammatory or surgical treatment should be prescribed. 2. When lymph node metastasis occurs in malignant tumors in the abdominal cavity, it can also cause a certain degree of enlargement of retroperitoneal lymph nodes, such as colon cancer, rectal cancer, etc., which should be treated by standardized medication and surgery as prescribed by doctors in time. Retroperitoneal lymph node enlargement is also seen in other reasons, which should consult doctor in time and standardize treatment under professional doctor’s guidance to avoid delaying the condition.