Pathology of tumours of the kidney and urinary tract

The urinary tract encompasses the kidney and the urinary collecting system, ureter, bladder and urethra. Benign lesions of the kidney include angiomyolipoma and renal oncocytoma. The main subtypes of renal cell carcinoma include clear cell, papillary and chromophobe variants. Prognostic factors reported by pathologists are reviewed, including the current grading and staging systems. Urothelial tumours include urothelial carcinoma in situ, papillary urothelial carcinoma, and invasive urothelial carcinoma. Aspects of their grading and staging are covered, and several less common variants and benign urothelial lesions are mentioned. General aspects of core biopsy and resection specimens for renal disease are examined, including indications for frozen section examination.