Magnetic resonance neurography for the diagnosis of extrapelvic sciatic endometriosis

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

Case report.

Academic teaching hospital.

A 39-year-old woman with a 4-year history of sciatica related to the menstrual cycle.

Surgical exploration of the sciatic notch for diagnostic confirmation, external neurolysis of the sciatic nerve, and eventual pharmacologic treatment.

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.

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.

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.