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

Aim 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. Materials and methods 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. Results 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 >5.4 cm ( 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 >5.4 cm diameter, the AUC was 0.66 (95% CI: 0.52–0.80) with 68.4% sensitivity and 62.7% specificity. Conclusions The DEC sign may predict aggressive biological behaviour of ccRCC, irrespective of tumour size.