UroToday.com - Large urothelial carcinoma of the renal pelvis poses a diagnostic as well as surgical challenge to the urologist. This type of malignancy is frequently mistaken preoperatively for renal cell cancer due to its low incidence (10% of all renal malignancies) especially when associated with tumor extension into the inferior vena cava. The presence of a large renal mass should therefore not dissuade the urologist to perform cystoscopy and cytology in order to complete hematuria work-up. Opening the specimen in the operating room will provide clues for the origin of the tumor.