[Value of clear cell likelihood score in differentiation between renal oncocytoma and clear cell renal cell carcinoma].

Objective: To evaluate the value of clear cell likelihood score (ccLS) in identifying renal oncocytoma (RO) and clear cell renal cell carcinoma (ccRCC). Methods: Retrospective data of pathologically confirmed 43 RO patients [24 men and 19 women, aged 22-77 (54±14) years] between February 2008 and September 2021 and 43 ccRCC patients [30 men and 13 women, aged 29-78 (56±12) years] between May and July 2021 were consecutively included in the department of radiology, Chinese PLA General Hospital. Two radiologists used ccLS to assess each case independently, and disagreements were resolved by consensus. The ability of ccLS to identify RO and ccRCC was examined by the receiver operating characteristic (ROC) curve which identified the best optimal diagnostic cut-off values, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Results: The mean tumor diameter was 3.8 cm in RO patients and 3.7 cm in ccRCC patients. Central scar and segmental enhancement inversion (SEI) were more frequently observed in the RO group compared to the ccRCC group [53.5% (23∶43) versus 11.6% (5∶43) and 41.9% (18∶43) versus 7.0% (3∶43), respectively], with statistical differences (P<0.001). The ccLS scores in the RO group ranged from 1 to 4, while 79.0% of the cases were 3. The ccLS scores in the ccRCC group ranged from 2 to 5, while 72% of the cases were 4. The scores of the two groups were statistically different (P<0.001). The ccLS showed the best performance when the threshold was 4 according to the ROC curve. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of ccLS for distinguishing RO from ccRCC were 83.7%, 90.7%, 87.2%, 90.0%, and 84.8%, respectively, and the area under the ROC curve value was 0.879. Conclusion: The ccLS has credible sensitivity and specificity in differentiating renal oncocytoma from clear cell carcinoma, which may be helpful for the preoperative diagnosis.