Sequence of TB infection in kidney.
Stenosis of calyceal neck or pelvic ureteric junction → Hydronephrosis and pyonephrosis → Perinephric abscess → Kidney replaced by caseous material (puty kidney) → Calcifcation → Autonephrectomy (a calcifed non-functioning kidney, representing end-stage disease).
Autonephrectomy is the fnal result of marked parenchymal fbrosis and obstructive uropathy.