Iliac artery aneurysms are rare, they represent less than 2% of abdominal aneurysms. External iliac arterial involvement is very rare. Pseudoaneurysms are abnormal dilatations of arteries bounded only by the tunica adventitia. They are commonly associated with trauma. Yin-yang sign is an ultrasound feature described in pseudoaneurysms. A contrast-enhanced CT study might help confirm the diagnosis.