May Be Caused by

Abscess

Acute pyelonephritis

Angiomyolipoma

Arterial branch occlusion

Arteriovenous malformation

Autosomal dominant polycystic kidney disease

Cyst

Infarction

Intrarenal hematoma

Localized hydronephrosis

Lymphoma

Medullary cystic kidney disease

Metastasis

Renal artery aneurysm

Renal cell carcinoma

Renal contusion

Renal laceration

Renal sinus lipomatosis

Sarcoma

Transitional cell carcinoma

Trauma

Tuberculosis

Wilms tumor

Xanthogranulomatous pyelonephritis