APLASIA OF THE LOWER POLE OF THE KIDNEY
This 79 year old male died from peritonitis following perforation of a carcinoma of the recto-sigmoid junction. The lesion demonstrated was an incidental finding at necropsy.
The specimen is a kidney 7.5 cm in length which has been cut in its long axis. The upper pole is normal apart from mild cortical narrowing. The mid zone and lower pole are represented by a tiny portion of renal tissue 1.5 x 1.0 cm in diameter, seen as a depressed zone at the lower border of the specimen. There is patchy haemorrhage and peri-vascular fibrosis in this atrophic renal tissue. The pelvi-calyceal system is dilated, and the dilatation is most marked inferiorly in the region where the renal parenchyma is greatly reduced or absent. This is an example of aplasia of the lower pole of the kidney.
This lesion is probably vascular in origin and is probably a congenital malformation.