The left ascending lumbar vein: a potential pitfall in CT diagnosis.

A communication between the left ascending lumbar vein and the left renal vein may be mistaken for a para-aortic mass on abdominal computed tomography due to a localised dilatation at the confluence of these veins. The use of contiguous closely collimated sections and the injection of intravenous contrast medium overcomes this potential pitfall which may be particularly important in the staging of patients with testicular neoplasms.