Transitional cell carcinoma obstructing a calyceal diverticulum: unusual presentation as a peripheral cystic mass.

Abstract

Transitional cell carcinoma, while being the most common tumor of the urinary tract overall, is a relatively uncommon tumor when the upper urinary tract is considered separately. In the kidney, adenocarcinoma occurs more often than transitional cell carcinoma by a ratio of 4:1 to 5:1.1 When transitional cell carcinomas occur in the upper urinary tract, they are usually located in the proximal ureter or the renal pelvis.2 The typical presentation of transitional cell carcinoma on excretory urograms and CT scans is a filling defect produced by a central, solid tumor that does not distort the renal outline.1 We report a transitional cell carcinoma obstructing a calyceal diverticulum that appeared as a peripheral complex cystic mass projecting laterally and distorting the upper pole of the kidney. The possibility that a peripheral cystic upper urinary tract lesion might be a transitional cell carcinoma, rather than a renal adenocarcinoma, has important implications for both the clinician and surgeon.