Unruptured abdominal aortic aneurysm mimicking hip joint disease.

A 66-year-old man with an 8-month history of progressive left hip pain was found to have a large unruptured infrarenal aortic aneurysm. The hip pain abated after aneurysm repair. His clinical picture suggested that the hip pain was caused by aneurysmal sac encroachment upon a nerve branch of the lumbar plexus. We report this previously unrecognized association to heighten awareness of this atypical but potentially life threatening cause of hip pain.