[Chronic pyelonephritis as a false interpretation in the excretory urogram].

Chronic pyelonephritis, which is largely diagnosed via imaging procedures, is characterised by defined parenchymal scars that become manifest in the excretory urogram as contour recessions of the kidney and result in deformations of the calyces and papillae. The authors describe other renal diseases, dysplasias, variations from the standard, and artifacts resulting in similar signs on x-ray film, thus leading to the wrong diagnosis of chronic pyelonephritis. The essential differential diagnostic criteria are explained.