Lumbosacral plexopathy due to common iliac artery aneurysm misdiagnosed as intervertebral disc herniation.

We report a case of lumbosacral plexopathy caused by an isolated aneurysm in the common iliac artery. The patient presented with low back and buttock pain radiating to the right leg and numbness in the L5 and S1 dermatomes. A computed tomography scan showed an aneurysm of the right common iliac artery. This case serves to increase awareness of the possibility of lumbosacral plexopathy in patients with symptoms of a prolapsed intervertebral disc.