Renal pelvic and ureteral wall thickening in renal cell carcinoma: prevalence, cause, and clinical significance

Purpose This study was performed to characterize renal pelvic and ureteral wall thickening (PUWT) in renal cell carcinoma (RCC) patients, including prevalence, cause, and detailed radiological findings based on contrast-enhanced CT, and to correlate these features with corresponding pathological findings. Materials and methods 152 patients pathologically diagnosed with RCC by surgery were included. Two radiologists retrospectively evaluated the presence of PUWT and the radiological characteristics based on CT. Relationships among clinical characteristics, CT findings, and PUWT were evaluated. Pathological findings of PUWT were also investigated. Results The prevalence of RCC-related PUWT was 10% ( N = 15). PUWT was frequently observed in cases with advanced TNM stage. Tumor thrombus, sinus extent, and peritumoral neovascularity were significantly more frequent in cases with PUWT. PUWT was observed at the pelvis or from the pelvis to the upper ureter. Fourteen of 15 cases in which the pelvic/ureteral wall was pathologically investigated did not show any pathological abnormalities. Conclusion The prevalence of PUWT was 10% and most cases were thought to be caused by temporary vascular dilatation in the pelvis and ureter, which is a secondary condition caused by hypervascular RCC, and not a direct result of tumor invasion.