腎盂内に腫瘍進展を来たし, 尿管から膀胱内へ連続するフィブリン栓を形成した腎細胞癌の1例

We present a case of renal cell carcinoma growing into the renal pelvis with a fibrin cap in the ureter and bladder. A 66-year-old man presented to our hospital with anemia and gross hematuria. Computed tomography showed a large left renal tumor and space-occupying lesions in the left renal pelvis and ureter. Cystoscopy showed a 2 cm-restiform mass protruding from the left ureteral orifice. We performed open left nephroureterectomy, and there was a 3 cm white mass with a smooth surface in the bladder. Pathological examination of the resected mass revealed clear cell carcinoma with urinary collecting system invasion and fibrin cap in the ureter and bladder. As a result, it would have been difficult to make the diagnossis of renal cell carcinoma preoperatively if we had performed biopsy of the mass in the bladder or ureter. The patient was diagnosed as having lung metastases 5 months after surgery. Urinary collecting system invasion has been considered an independent prognostic factor in pT3 renal cell carcinoma.