Computed Tomography Imaging Appearance of a Unique Variant of Retroiliac Ureter.

Retroiliac ureter is a rare condition where the ureter passes behind the iliac vessels. The diagnosis is usually intraoperative and the reports of preoperative imaging diagnosis are scarce. Herein, we report the computed tomography appearance of a unique variant in which the right ureter partially encircles the right common iliac artery bifurcation; passing first in front of the common iliac artery and then medial to the artery and finally posterior to the external iliac artery, and then regains its normal course in the pelvis.