Isolated iliac artery aneurysms with associated hydronephrosis.

An isolated iliac artery aneurysm is where there is aneurysmal dilatation of one or more branches of the iliac system, with no associated dilatation of the aorta. Such aneurysms are rare and comprise 1% of all intra-abdominal aneurysms. The signs and symptoms of such an aneurysm are influenced by its concealed location within the bony pelvis. Awareness of these special characteristics improves the chances of early diagnosis and proper treatment before possible rupture. We present the clinical and radiological features of three such aneurysms. Ultrasound was the first imaging modality to be performed. Ipsilateral hydronephrosis was demonstrated in each case, this lead to imaging the pelvis and the correct diagnosis. We review the clinical and radiological literature and conclude that the pelvis should be imaged in all cases of unexplained hydronephrosis.