Solution: Only 8% of Transitional cell carcinoma arises within the kidney with the large majority (90%) occurring in the urinary bladder. Although calcifications are described in TCC, only 2% of renal pelvis TCC will actually calcify. In this case, since the exam was not performed as a CT Urography, the findings are not necessarily obvious. There is a infiltrative, hypovascular mass within the left renal collecting system, with associated expansion of the left renal pelvis and some subtle prominence of the upstream calyces. The person interpreting this exam recognized these findings and obtained delayed images, which were quite revealing. TCC is treated surgically with total nephroureterectomy and bladder cuff excision unless there are metastases in which case they are treated with chemotherapy and/or radiation.