Diagnosis: Urothelial carcinoma of the renal pelvis infiltrating the kidney parenchyma.   

            Comment: The clear cell areas (Figs. 1 and 2) are rich in glycogen and may mislead to an erroneous diagnosis of  clear cell kidney carcinoma. Fig. 3 shows microscopic features of a typical urothelial carcinoma and Figs. 4 and 5 show squamous differentiation.