【Abstract】 ObjectiveTo study the incidence and analyze the predictive factors of benign renal occupation in Chinese patients with preoperative imaging diagnosis of renal cancer who underwent partial nephrectomy or radical nephrectomy. METHODS: A total of 1531 patients diagnosed with renal cancer by preoperative imaging and underwent partial nephrectomy or radical nephrectomy from January 2003 to September 2010 were retrospectively analyzed, and the clinicopathological data of the patients with postoperative pathological confirmation of benign renal occupancy were analyzed by multifactorial regression. RESULTS: A total of 81 (5.3%) of 1531 patients were benign, including 52 (3.4%) vascular smooth muscle lipomas, 12 (0.8%) eosinophilic cell adenomas, 6 (0.3%) complex cysts, and 11 (0.7%) other types. Univariate analysis showed that females, tumors with smaller maximum diameters, younger age, and cystic occupations as clinical manifestations were more likely to be pathologically confirmed as benign. Multifactorial regression analysis showed that being female (OR, 3.13; 95% CI, 1.95-5.04; P < 0 .001), having a smaller tumor maximum diameter (OR,0.75; 95% CI,0.66-0.85; P < 0 .001), and younger age (OR, 0.94; 95% CI, 0.92-0.96; P < 0 .001) were independent predictors of benign occupancy. independent predictor. In contrast, cystic occupancy was not a significant predictor. CONCLUSION: In Chinese patients, the incidence of preoperative imaging diagnosis of renal cancer confirmed as benign by postoperative pathology was 5.3%, which was significantly lower than that of similar foreign studies. The most common type of benign occupancy was vascular smooth muscle lipoma, compared with eosinophilic cell adenoma in similar studies in Europe and the United States. Female, younger age, and smaller maximum tumor diameter were independent predictors of benign occupations. Ji-Wei Huang, Department of Urology, Shanghai Renji Hospital, Shanghai, China