Diagnostic value of MDCT in determining the perinephric fat tissue and renal sinus invasion in patients with clear cell renal cell carcinoma.

Aims: To investigate the accuracy of multidetector computed tomography (MDCT) findings, and the effect of tumor volume in determining the perinephric and renal sinus invasion in clear cell renal cell carcinomas (ccRCCs).

Method: Fifty patients with ccRCCs underwent non-contrast and nephrographic-phase contrast-enhanced MDCT examination before total nephrectomy. The following MDCT features were used to diagnose perinephric fat tissue invasion: perinephric stranding, perinephric vascularity, and irregular contour. The following MDCT features were used to diagnose renal sinus fat invasion: elongation of tumor into renal sinus, invasion, or compression of pelvicalyceal system. Histopathologic examinations were used as a gold standard.

Results: Fourteen out of 50 ccRCCs patients (28%) had histopathological-proven perinephric fat tissue invasion. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in the detection of perinephric fat tissue invasion were found 64%, 58%, 38%, 80%, and 60%, respectively. Seven out of 50 ccRCCs patient (14%) had histopathological-proven renal sinus invasion. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in the detection of renal sinus invasion were found 85%, 65%, 28%, 96%, and 68%, respectively. The area under of curve (AUC) value of tumor volume in the detection of perinephric fat invasion was 0.631. The AUC value of tumor volume in the detection of renal sinus invasion was 0.803.

Conclusion: MDCT has a good sensitivity for detection of renal sinus fat invasion, but low PPV and specificity in patients with ccRCC. Tumor volume, and invasion into the pelvicalyceal structures can aid in the diagnosis of renal sinus fat invasion preoperatively.