May Be Caused by

 Common

Collateral paraureteral artery

Collateral paraureteral vein

Normal accessory renal artery

Normal iliac artery

 Uncommon

Aortic aneurysm

Arteriovenous communication of renal or juxtarenal vessels

Azygos continuation of inferior vena cava

Cirsoid aneurysm of renal artery

Iliac artery aneurysm

Lymphangiectasis

Lymphangioma

Normal gonadal vein

Varices of broad ligament

Varices of gonad

Varices of ureter