Figure 9e. Transitional cell carcinoma of the renal pelvis and ureteral perforation that occurred during ureteroscopy in a 47-year-old man. (a-c) Axial unenhanced (a), nephrographic-phase (b), and excretory-phase (c) CT scans demonstrate an enhancing soft-tissue mass in the renal pelvis (arrows) with no invasion of the renal parenchyma. (d, e) Axial CT scan (d) and coronal MIP image (e) demonstrate a large collection of contrast material (arrowheads) adjacent to the ureter (arrow in d) due to perforation of the proximal ureter. The irregular filling defect in e (arrows) represents transitional cell carcinoma.