title: Rapid, symptomatic enlargement of a lumbar juxtafacet cyst: case report.
abstract: METHODS
  A case is reported in which a 45-year-old man developed cauda equina syndrome caused by enlargement of an L4-L5 juxtafacet cyst diagnosed 4 months earlier.
  
  
  OBJECTIVE
  To highlight the short interval that can elapse between the discovery of a juxtafacet cyst and its remarkable progression.
  
  
  BACKGROUND
  Although juxtafacet cysts are acquired lesions, how long they take to develop remains unclear. Hemorrhage is a well-known cause of rapid or even dramatic cyst enlargement. This is the first report providing magnetic resonance imaging evidence of rapid, remarkable enlargement of a nonhemorrhagic juxtafacet cyst.
  
  
  METHODS
  The patient underwent conservative treatment for an L4-L5 right juxtafacet cyst diagnosed by magnetic resonance imaging during evaluation of posttraumatic lower back pain. Four months later, the patient presented with severe pain radiating down the right lateral leg, urinary retention, and impaired dorsal flexion of the right foot. Repeat magnetic resonance imaging showed the cyst now markedly enlarged and occupying almost the entire width of the canal.
  
  
  RESULTS
  The cyst was removed, and the patient's symptoms abated. At 15 months after surgery, he is symptom-free.
  
  
  CONCLUSIONS
  Juxtafacet cyst may occasionally enlarge and cause severe symptoms within months.
authors.affiliation: Department of Neurological Sciences, Neurosurgery, Az. Osp. S. Maria, Terni, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Paolini
authors.forename: Pasquale
authors.initials: P
authors.lastname: Ciappetta
authors.forename: Antonio
authors.initials: A
authors.lastname: Santoro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ramieri
mesh_terms: D003560:Cysts / Q000150:complications* / Q000175:diagnosis* / Q000601:surgery; D018450:Disease Progression; D006801:Humans; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011128:Polyradiculopathy / Q000175:diagnosis* / Q000209:etiology*; D013124:Spinal Injuries / Q000150:complications; D021801:Zygapophyseal Joint / Q000601:surgery