Solution: Transitional cell carcinoma represents the majority of uroepithelial cancers (90+%) with less common squamous cell and adenocarcinoma contributions. There is a male predominance and it generally occurs in patients older than 60. When there is invasion of the kidney, it is associated with an appearance as seen in this case, i.e. infiltrative tumor that preserves the overall renal shape. The enhancement is usually minimal. 90% of TCC's occur in the bladder with 8% in the kidney/renal pelvis and 2% in the ureters. The primary differential considerations include: renal cell carcinoma, infection, both tuberculosis and other infiltrative infections, and lymphoma. Unlike RCC, treatment of TCC requires excision of the entire ureter in addition to the kidney. They are at lifetime increased risk of recurrent disease and have annual follow up imaging for life.