Objective To improve the diagnosis and treatment of benign renal tumor so as to avoid overtreatment.Methods The clinical data of 9 cases with benign renal tumor misdiagnosed as renal cell carcinoma treated from May 1999 to May 2011 were retrospectively analyzed.All cases were misdiagnosed as renal cell carcinoma with ultrasound or computed tomographic imaging before operation.Results All cases underwent surgical operation.For 1 case,frozen pathological test suggested a benign outcome.The tumor was enucleate accordingly.For another 7 cases,radical nephrectomy were performed.For the last 1 case,simple nephrectomy was performed.All cases were confirmed as benign by postoperative pathologic test,including 6 cases of renal angiomyolipoma,2 cases of renal oncocytoma,1 case of metanephric adeoma.Follow-up assessment lasted for (1-5) years without recurrence or metastasis.Conclusions It must be paid special attention to unique features which benign renal tumor shows in medical imaging.When the diagnosis is inconclusive,nephrectomy can be avoided by further intraoperative frozen pathological test to avoid overtreatment.