Progressing left-side sciatica revealing a common iliac artery mycotic aneurysm in an elderly patient

Rationale: Sciatica is usually caused by lumbar spine disease; the incidence of sciatica from extra-spinal causes is noted to be only about 0.09%. Patient concerns: We report a case of a 92-year-old man who came to the neurologist outpatient department due to left buttock pain and numbness that radiated to the left lower leg in the recent 6 months and progressed rapidly over 10 days. Diagnosis: We arranged magnetic resonance imaging for lumbar nerve lesion. Magnetic resonance imaging showed a common iliac artery mycotic aneurysm, at about 6.3 cm in diameter, which compressed the psoas muscle, nerve plexus, and vein. Interventions: We used a left-side iliac bifurcation stent graft of 12 mm in diameter for aneurysm repair. An internal iliac artery with a stent graft of 10 mm x 5 cm. An abdomen aortic aneurysm stent was inserted, 1 cm beneath the right renal artery from the right side femoral artery. Outcomes: After endovascular repair and 4 weeks of antibiotic treatment, he could walk again, and no sciatica was noted. We repeated computed tomography 5 months after the operation and noted that the size of the iliac artery aneurysm decreased without stent graft migration or extravasation. Our patient recovered from sciatic and left leg weakness; above all, he could walk again. Lessons: We suggest practitioners check for common iliac artery aneurysms in the diagnosis of symptoms mimicking spinal cord origin sciatica, especially in elder patients.