ObjectiveTo explore the application of MDT mode in the diagnosis and treatment of a large retroperitoneal small cell carcinoma.MethodsA huge retroperitoneal tumor about 25 cm×18 cm was found by the preoperative abdominal MRI examination, which was considered as the malignant tumor. Considering the patient’s condition, MDT consultation of the specialists in radiology, oncology, vascular surgery, urinary surgery, and anesthesiology was conducted.ResultsBy MDT discussion, the general condition of patient was good. At present, the diagnosis of the huge retroperitoneal tumor was confirmed. Although the tumor was surrounded with related organs closely, yet the radical operation was finished smoothly and the R0 resection was achieved through the collaboration of MDT. The operation lasted 365 minutes, and the intraoperative blood loss was about 200 mL. Postoperative pathology confirmed that the tumor margin was negative and no postoperative complication occurred. The total number of hospital stays was 23 days. The patient’s return to the hospital for review in 4 months after discharge revealed a tumor recurrence. Then, combined with radiotherapy and chemotherapy, the patient’s condition was stable during treatment.ConclusionFor rare cases of retroperitoneal small cell carcinoma involving multiple disciplines, the treatment based on MDT is able to bring better clinical outcome to patients due to safer and more feasible.