[Urothelial tumors of the kidney].

Urothelial tumors of the kidney arise from the urothelium of the renal pelvis. Most of them are transitional cell carcinomas histologically similar to bladder carcinomas. The new staging system emphasizes the role of kidney parenchyma in the spread of the tumor. Homolateral multifocal lesions are frequent, along with bladder lesions, preceding, simultaneous with or subsequent to upper tract tumor.