title: Symptomatic cervical synovial cyst associated with an os odontoideum diagnosed by magnetic resonance imaging: case report and review of the literature.
abstract: METHODS
  The first case of a synovial cyst of the upper cervical spine associated with os odontoideum diagnosed by magnetic resonance imaging is presented.
  
  
  OBJECTIVE
  To evaluate distinct magnetic resonance imaging findings of a cervical synovial cyst located anterior to the cord and discuss its association with os odontoideum. These findings may guide further investigations.
  
  
  BACKGROUND
  Synovial cysts of the spine are uncommon findings. They occur mostly dorsolaterally and with greatest frequency in the lumbar spine and are rarely symptomatic. No association with os odontoideum has been reported before.
  
  
  METHODS
  A single subject with symptoms of deterioration in his hand functions was examined by a 2. 0-T magnetic resonance imager.
  
  
  RESULTS
  Magnetic resonance imaging of the cervical spine showed an os odontoideum connected to the body of C2 by a synovial joint that had a cystic extension posteriorly compressing the cord.
  
  
  CONCLUSIONS
  Synovial cysts should be considered in the differential diagnosis of an extradural mass of the upper cervical spine. Magnetic resonance imaging should be the choice in the investigation of such cases.
authors.affiliation: Department of Radiology, Ankara Training and Research Hospital, Ankara, Turkey. fgaksoy@hotmail.com
authors.forename: F G
authors.initials: FG
authors.lastname: Aksoy
authors.forename: J M
authors.initials: JM
authors.lastname: Gomori
mesh_terms: D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009809:Odontoid Process / Q000473:pathology*; D013581:Synovial Cyst / Q000473:pathology*