大的肾结石阻塞了肾脏下极的肾盏，导致了局部的肾盂积水。梗阻、扩张引起的肾盂积水导致了感染。扩张肾盏的表面粘膜充血，靠近扩张肾盏的区域为黄褐苍白区，这是炎症感染的特征。肾上极正常，皮、髓质分界清楚。
There was a large renal calculus (stone) that obstructed the calyces of the lower pole of this kidney, leading to a focal hydronephrosis (dilation of the collecting system). The stasis from the obstruction and dilation led to infection. The infection with inflammation is characterized by the pale yellowish-tan areas next to the dilated calyces with hyperemic mucosal surfaces. The upper pole is normal and shows good corticomedullary demarcations.
