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

ABSTRACT

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.