摘要Background Wilms tumor tends to grow into vena cava,even invade atrium,which increased operating difficulty and fre-quency of surgical complications.Methods Forty-two patients of Wilms tumor with intravenous thrombus were retrospective studied.The diagnosis and therapy were discussed according to the medical records and interrelated literatures.Results Forty-two children with thrombus were diagnosed by computed tomography and 41 cases by ultrasound simultane-ously.36 children had received preoperative chemotherapy.Surgical resection was performed in all patients.Cardiopulmonary bypass was used for the removal of the intra-atrial thrombus in 5 patients.There were no surgical complications occurred.The patients received chemotherapy and radiotherapy according to clinical staging by National Wilms'Tumor Study(NWTS)-4 or NWTS-5.34 patients were successfully followed up,32 patients survive at present,including one who has been followed up more than 20 years since operation.Conclusion Standardized sequential treatment,including preoperative chemotherapy and radiotherapy,nephrectomy com-bining resection of thrombus,postoperative adjuvant therapy,is the mainstay of treatment of Wilms tumor with intravenous thrombus.