Magnetic resonance neurography for the diagnosis of extrapelvic sciatic endometriosis

Objective: To illustrate magnetic resonance neurography findings of severe sciatic injury and muscle denervation related to deep gluteal endometriosis at the sciatic notch.

Design: Case report.

Setting: Academic teaching hospital.

Patient(s): A 39-year-old woman with a 4-year history of sciatica related to the menstrual cycle.

Intervention(s): Surgical exploration of the sciatic notch for diagnostic confirmation, external neurolysis of the sciatic nerve, and eventual pharmacologic treatment.

Main outcome measure(s): Magnetic resonance neurography imaging revealed severe neuropathic injury and muscle denervation related to a deep infiltrative endometriotic focus at the sciatic notch, which was confirmed histologically on surgical exploration. Detailed electrodiagnostic and clinical neurologic examinations at initial presentation and during follow-up were obtained for further assessment of nerve degeneration, muscle denervation, and clinical recovery.

Result(s): Initial gynecologic and eventual laparoscopic evaluation on persisting complaints were without pathological findings. When a progressive weakness of the leg was noted, magnetic resonance neurography revealed a severe axonal damage to the sciatic nerve and denervation of distal target muscles related to a diffuse infiltrative lesion at the sciatic notch. On surgical exploration, extragenital endometriosis was confirmed histologically. Considerable improvement in pain and strength occurred after pharmacologic therapy with a GnRH analogue.

Conclusion(s): This is the first report to describe imaging findings of magnetic resonance neurography in severe neuropathic injury of the sciatic nerve and subsequent muscle denervation related to a deep infiltrative gluteal endometriotic focus.