title: An enterogenous cyst with atypical pathological findings and chemical meningitis.
abstract: BACKGROUND
  Intracranial enterogenous cysts are rare and mainly occur in the posterior fossa. These cysts are usually extra-axial, midline, anterior to the brainstem, or at the cerebellopontine angle. We report a case of an enterogenous cyst in which diagnosis was difficult because the lesion showed atypical pathologic findings.
  
  
  METHODS
  A healthy 41-year-old man complained of paroxysmal occipital headaches lasting over a week, with increased severity for 3 days accompanied by slight dizziness and mild nausea. Magnetic resonance imaging showed a cystic lesion between clivus and brainstem. The patient underwent surgery for removal of the lesion via the right-sided far-later approach, and the lesion was resected totally. Although pathologic examinations showed a cyst had a mono-to-multilayered squamous epithelium, which are not accord with typical enterogenous cyst, the diagnosis was finally made based on the presence of basement membrane and immunohistochemical results.
  
  
  RESULTS
  To confirm the diagnosis of enterogenous cyst, further pathologic examinations were performed and immunohistochemical characters were summarized. Chemical meningitis, a rare complication of enterogenous cyst, happened in current case. Use a syringe and aspirate the contents before incision might be a procedure to prevent chemical meningitis.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of an enterogenous cyst associated with mono-to-multilayered squamous epithelium. Although during the follow-up time, no recurrence happened, long-term follow-up is needed.
authors.affiliation: Department of Neurosurgery, The China-Japan Union Hospital, Jilin University, Changchun, 130033 Jilin People's Republic of China.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, Bethune Medical School, Jilin University, Changchun, 130021 Jilin People's Republic of China.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, The China-Japan Union Hospital, Jilin University, Changchun, 130033 Jilin People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Neurosurgery, The China-Japan Union Hospital, Jilin University, Changchun, 130033 Jilin People's Republic of China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, The China-Japan Union Hospital, Jilin University, Changchun, 130033 Jilin People's Republic of China.
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Fang
keywords: Enterogenous cyst; Immunohistochemistry; Meningitis; Neurenteric cyst