Aorto-left renal vein fistula caused by a ruptured abdominal aortic aneurysm.

Retroaortic left renal vein is a malformation in which the left renal vein courses dorsal to the abdominal aorta. In patients with abdominal aortic aneurysm, an aorto-left renal vein fistula can form if the left renal vein is sandwiched between the aneurysm wall and lumbar vertebrae. The patient was an 84-year-old man with lower back pain. We performed a contrast-enhanced computed tomography (CT), although renal dysfunction was noted. The CT showed a ruptured juxta-renal abdominal aortic with aorto-left renal vein fistula. This clinical condition can cause severe renal dysfunction, in spite of which an enhanced contrasted CT scan would be extremely informative preoperatively.