Cyclic Sciatica: A Manifestation of Compression of the Sciatic Nerve by Endometriosis: A Case ReportDhôte, Robin MD*; Tudoret, Loïc MD†; Bachmeyer, Claude MD*; Legmann, Paul MD†; Christoforov, Boyan MD*Spine: October 1st, 1996 - Volume 21 - Issue 19 - p 2277–2279 Case Report Abstract Author Information Study design A case of cyclic sciatica secondary to ovarian cyst endometriosis is presented. Objectives To report the clinical description and magnetic resonance imaging aspects of cyclic sciatica. Summary of Background Data Endometriosis of the sciatic nerve is rare, but must be included in the differential diagnosis of sciatic mononeuropathies. Methods The authors report a new case of a woman whose cyclic sciatica was caused by an ovarian cystic endometriosis lesion. Results Magnetic resonance imaging was described as hyper- and hypointense on T1-weighted sequences, and hyperintense on T2-weighted sequences at the sciatic notch. Conclusion Magnetic resonance imaging may permit a specific diagnosis of this unusual cause of sciatica by showing a hemorrhagic mass in the region of the sciatic nerve. Early recognition is necessary to prevent permanent damage to the sciatic nerve. From *Service de Médecine Interne and †Service de Radiologie A, Hôpital Cochin, Paris, France. Acknowledgment date: May 1, 1995. First revision date: November 28, 1995. Acceptance date: December 20, 1995. Device status category: 1. Address reprint requests to: Robin Dhôte, MD; Service de Médecine Interne; Hôpital Cochin; 27 rue du Faubourg Saint-Jacques; 75979 Paris cedex 14; France © Lippincott-Raven Publishers.