May Be Caused by

 Common

Chronic atrophic pyelonephritis

Infarction

Ischemia

Partial nephrectomy

Postobstructive renal atrophy

Reflux nephropathy

Traumatic renal atrophy

 Uncommon

Healed abscess

Interstitial nephritis

Radiation therapy

Renal papillary necrosis

Renal segmental hypoplasia

Renal vein thrombosis

Tuberculosis