Diagnosis: Hydronephrosis + chronic inespecific pyelonephritis.   

            Comment: The gross examination of the surgical specimen showed dilated pelvis and calices, and atrophic parenchyma with scars. The microscopic examination showed flattened papillae (Fig.1), chronic inespecific interstitial inflammatory infiltrate with presence of lymphoid follicles (Fig.2), and fibrosis involving the renal corpuscles. A striking finding in this case was tubular rupture with expulsion of Tamm-Horfall protein from the tubule into the interstitium (Figs. 3,4 e 5). This may frequently occur in hydronephrosis.