The elbow suddenly swollen a soft big bag may be tendon sheath cysts, bursitis, sebaceous cysts and other diseases, the patient can take medication, surgical treatment, chemotherapy, rehabilitation exercise and other treatment. 1. Tendon sheath cysts: For tendon sheath cysts caused by the elbow suddenly swollen a soft big bag, if the combination of pain, the patient can follow the doctor’s instructions oral aspirin tablets, celecoxib capsules and other non-steroidal anti-inflammatory drugs. In addition, patients can also take surgical treatment, such as complete cystectomy. Tendon sheath cyst patients after treatment should be under the guidance of the doctor to carry out rehabilitation exercises, patients can move the elbow, flexion and extension exercises, but should pay attention to the amplitude as well as the training time. 2. Bursitis: bursitis can also lead to the patient’s elbow suddenly swollen with a large soft bag of symptoms, the patient can follow the doctor’s instructions oral ibuprofen extended-release capsules, diclofenac sodium extended-release tablets and other non-steroidal anti-inflammatory drugs, but also the use of prednisolone acetate injection, hydrocortisone succinate injection and other glucocorticosteroid drugs. Patients can also take surgical treatments such as bursal resection. Patients with bursitis should follow the doctor’s instructions to take rehabilitation training after treatment, flexion and extension of the elbow with the help of the doctor or family members, which is conducive to postoperative recovery. 3. synovial sarcoma: for synovial sarcoma caused by elbow suddenly swollen a soft big bag, the patient can follow the doctor’s instructions for surgical treatment, mainly to take the way of surgical resection treatment. After the surgery, patients should also follow the doctor’s instruction to use oral cyclophosphamide injection, vincristine injection and other chemotherapeutic drugs to carry on chemotherapy. After surgery, patients with synovial sarcoma should take rehabilitation exercise in time, and appropriate activity of the affected area can help patients recover. When the patient suddenly swelled up a big soft bag on the elbow, the patient should consult a doctor in time, and follow the doctor’s instructions for treatment after a clear diagnosis.