An unexpected etiology of lumbosciatica.

Lumbosciatica is a frequent symptom. When it is hyperalgic and/or deficient, it requires urgent exploration and an eventual surgical procedure. In most of the cases, medullary lumbar (instead of medullary) MRI is required looking in the first place at an intervertebral disc herniation. Other etiologies are rare but must be kept in mind. We report a case of a 37-year-old man with left L5 hyperalgic and deficient lumbosciatica. The conclusion of the etiological research led to pseudoaneurysm of the internal iliac artery compressing the ipsilateral sciatic nerve. The patient was operated on with a good clinical course.