On one side kidney is normal, while another side kidney is contracted with a scar, what is the most probable diagnosis?

CHRONIC PYELONEPHRITIS Morphology Even when involvement is bilateral, the kidneys are not equally damaged and therefore are not equally contracted. This uneven scarring is useful in differentiating chronic pyelonephritis from the more symmetrically contracted kidneys associated with vascular sclerosis (often referred to as benign nephrosclerosis) and chronic GN. The hallmark of chronic pyelonephritis is scarring involving the pelvis or calyces, or both, leading to papillary blunting and marked calyceal deformities. Ref: ROBBINS BASIC PATHOLOGY 10th ed Pg no: 566