Intrapiriformis lipoma: an unusual cause of piriformis syndrome

We report on a patient with an unusual cause of non-discogenic sciatica. A 48-year-old woman presented with a 10-day history of gradually worsening left buttock pain radiating to the ipsilateral posterior thigh and calf. She had a similar episode of less intense pain 8 months before which lasted about 2 months. She denied any history of antecedent trauma or back pain. MRI scan revealed a well-defined, fat-containing lesion of the left piriformis...