Xanthogranulomatous pyelonephritis--(a clinicopathological study of 15 cases).

The clinico-pathological features of 15 patients with xanthogranulomatous pyelonephritis (XGP) are described and the probable histogenesis is discussed. Based on our data and the review of literature, we believe that XGP should be regarded as a destructive and at times tumefactive inflammatory process that may complicate chronic pyelonephritis. The initiation of this process remains obscure, but the features commonly associated with XGP are pelvi-calyceal obstruction, ulceration of the pelvic urothelium with collection of necrotic material and bacterial infection.