Delayed enhancement of the peritumoural cortex in clear cell renal cell carcinoma: correlation with Fuhrman grade

Abstract

To assess the delayed enhancement of the peritumoural cortex (DEC) sign in clear cell renal cell carcinoma (ccRCC), and investigate a possible correlation among DEC and Fuhrman grade. This retrospective study included 506 patients with 511 histopathologically proven ccRCCs evaluated by computed tomography (CT) angiography. DEC was detected and compared in groups divided by Fuhrman grades (low grade: 1 and 2, high grade: 3 and 4) using univariate and multivariate analyses. DEC was detected in 89 of 511 (17.4%) ccRCCs (grade 1: 5.7%, 2/35; grade 2: 16.2%, 70/433; grade 3: 31.4%, 11/35; grade 4: 75%, 6/8; p<0.001). The incidence was higher in high-grade ccRCCs (39.5%, 17/43) than in low-grade ccRCCs (15.4%, 72/468; p<0.001). In multivariate analysis, tumour size >5.4cm (p<0.001, odds ratio [OR]=3.57, 95% confidence interval [CI]: 1.76-7.23) and detection of DEC (p=0.021, OR=2.33, 95% CI: 1.13-4.80) were independent predictors of high-grade ccRCC. For all ccRCCs, the area under the receiver operating characteristic (ROC) curve (AUC) of DEC in predicting high-grade ccRCC was 0.62 (95% CI: 0.53-0.72) with 39.5% sensitivity and 84.6% specificity, while for ccRCCs of >5.4cm diameter, the AUC was 0.66 (95% CI: 0.52-0.80) with 68.4% sensitivity and 62.7% specificity. The DEC sign may predict aggressive biological behaviour of ccRCC, irrespective of tumour size.