title: Bilateral symptomatic synovial cysts of the lumbar spine caused by calcium pyrophosphate deposition disease: a case report.
abstract: METHODS
  A case of bilateral symptomatic facet joint synovial cysts arising in association with calcium pyrophosphate deposition disease is reported.
  
  
  OBJECTIVE
  To present a previously unreported cause for symptomatic synovial cysts of the lumbar spine.
  
  
  BACKGROUND
  Synovial cysts of the facet joints occur most commonly in association with degenerative disease of the spine in older individuals. The association of these cysts with trauma, rheumatoid arthritis, spondylolysis, and kissing spinous processes also has been reported. These cysts can cause symptoms and signs from direct compression of the dura. Chondrocalcinosis has not been previously reported to cause symptomatic synovial cysts.
  
  
  METHODS
  A 67-year-old woman presented with right lower limb sciatica caused by a right L4-L5 facet joint cyst, which resolved after surgical decompression. A year later, she presented with left lower limb sciatica caused by development of a new L4-L5 facet joint cyst, which also resolved after surgical decompression.
  
  
  RESULTS
  Histopathologic examination of each cyst showed a cyst wall of fibrous tissue with synovial lining, inflammation, and granulation tissue. Examination of the tissue under polarized light showed positively birefringent, short blunt crystals of calcium pyrophosphate dihydrate.
  
  
  CONCLUSIONS
  In patients with a history of gout or pseudogout, a rare possibility of a synovial cyst should be considered in the differential diagnosis during investigation for the cause of neural compression resulting in sciatic syndrome.
authors.affiliation: Robert Jones and Agnes Hunt Orthopaedics Hospital, Oswestry, United Kingdom. anirudhha@gadgil.net
authors.forename: Anirudh A
authors.initials: AA
authors.lastname: Gadgil
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Eisenstein
authors.forename: Alan
authors.initials: A
authors.lastname: Darby
authors.forename: Victor
authors.initials: V
authors.lastname: Cassar Pullicino
mesh_terms: D000368:Aged; D002805:Chondrocalcinosis / Q000150:complications* / Q000175:diagnosis; D019299:Decompression, Surgical; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging; D012008:Recurrence; D012585:Sciatica / Q000175:diagnosis / Q000209:etiology; D013122:Spinal Diseases / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D013131:Spine / Q000473:pathology* / Q000601:surgery; D013581:Synovial Cyst / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D021801:Zygapophyseal Joint / Q000473:pathology* / Q000601:surgery