Enlarged mesenteric lymph nodes around the umbilicus may be due to lymph node tuberculosis, mesenteric lymphadenitis, lymphoma, other malignant tumors, and adverse drug reactions. The details are as follows: 1. Lymph node tuberculosis: it manifests as enlargement of lymph nodes in many places, including enlargement of periumbilical mesenteric lymph nodes. There are usually no special symptoms in the early stage of the disease, and with the development of the disease, there are manifestations such as low fever in the afternoon and night sweats. Lymph node tuberculosis can be clearly diagnosed through sputum bacterial culture and other tests, and timely anti-tuberculosis treatment is needed. 2. Mesenteric lymphadenitis: mostly occurs after upper respiratory tract and intestinal tract infections, and mainly manifests as fever, abdominal pain, nausea, vomiting, and enlarged mesenteric lymph nodes around the umbilicus. After clear diagnosis by blood routine, abdominal CT and other tests, fasting, infusion or oral antibiotic treatment is needed. 3. Lymphoma: malignant tumors of lymphatic system, such as acute lymphoma, can lead to multiple lymph node enlargement, including periumbilical mesenteric lymph node enlargement. The diagnosis should be clarified through blood routine and bone marrow aspiration, and the corresponding treatment plan should be used according to the patient’s condition. 4. Other malignant tumors: liver cancer, pancreatic cancer, colon cancer, etc. can lead to enlargement of periumbilical mesenteric lymph nodes. Patients may also have systemic manifestations such as wasting, low fever, etc. Lymph node biopsy can be used to confirm the diagnosis, and individualized treatment plan, such as surgery, radiotherapy, chemotherapy, etc., can be formulated according to patients’ conditions. 5. Adverse drug reactions: Isoniazid, phenytoin sodium and other drugs may cause periumbilical mesenteric lymph node swelling. Patients do not need to worry too much, usually after stopping the drug, lymph node enlargement can disappear on its own. If the swelling of periumbilical mesenteric lymph nodes occurs, patients should consult a doctor in time to identify the cause of the disease and carry out targeted treatment under the guidance of the doctor.