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: 1 October 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.