Focal xanthogranulomatous pyelonephritis simulating malignancy in children.

Xantogranulomatous pyelonephritis is a severe chronic form of renal parenquimal infection that usually results in diffuse renal destruction. An unusual case of xanthogranulomatous pyelonephritis in a child is reported which presented as a focal mass without calculus in a functioning kidney and was diagnosed as a renal tumor.