Objective:To improve the differential diagnosis between benign renal mass and renal cell carcinoma(RCC) so as to lower the misdiagnosis rate.Methods:A retrospective analysis was done on 21 cases of renal mass

aged ranged from 33 to 63 with a mean of 51.Among the 21 years

All of them were preoperatively diagnosed as RCC by imaging.Results:All the cases were surgically treated.Three cases underwent enucleation or simple nephrectomy because of the diagnosis as benign renal mass by intraoperative frozen section.Eight underwent radical nephrectomy.And the other 10 underwent simple nephrectomy.The pathological analysis after operation found all were renal benign changes.None developed recurrence during the follow-up of 1 to 5 years.Conclusions:Some renal benign space occupying masses could be misdiagnosed as renal cell carcinoma only by imaging examinations and surgical exploration and intraoperative frozen section by pathologic study were the keys to lower the misdiagnosis rate.