title: Malignant transformation of intra-cranial epithelial cysts: systematic article review.
abstract: BACKGROUND
  Epidermoid and dermoid cysts are among the most benign intra cranial tumors. Their malignant transformation into squamous cell carcinoma is rare. The authors reviewed the literature.
  
  
  METHODS
  MEDLINE and SCIENCE DIRECT searches, and examination of the references in the selected articles yielded 74 patients, 52 of whom fulfilled Garcia's criteria and were selected for the study. Survival analyses were performed to determine whether survival differences were of statistical significance, and P < 0.05 was considered as significant.
  
  
  RESULTS
  Malignant transformation is characterized by a rapid onset of symptoms, recurrence, leptomeningeal carcinomatosis (LC), and tumor enhancement at Computed Tomography Scan or Magnetic Resonance Imaging (87.8 showed this radiological feature). In this review, the SCCs were classified in five groups: (1) Initial malignant transformation of a benign cyst; (2) malignant transformation from a remnant cyst; (3) malignant transformation of a dermoid and epithelial cyst; (4) malignant transformation with leptomeningeal carcinomatosis; (5) other malignancies arising from benign cysts. The median survival was 9 months. Statistics show that LC was of poor prognosis and radiotherapy, although not statistically significant, seems effective against such lesions, with a median survival of 26 months as opposed to 3 months (P=0.077).
  
  
  CONCLUSIONS
  Although rare, malignant transformation of intracranial epithelial cysts has a poor prognosis and surgery followed by radiotherapy seems to be the best therapeutic modality.
authors.affiliation: Department of Neurosurgery, Service de Neurochirurgie, CHRU Pontchaillou, Rue Henry Le Guilloux, 35000 Rennes Cedex 2, France. hamlat.abd@wanadoo.fr
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Hamlat
authors.forename: Zhi-Fen
authors.initials: ZF
authors.lastname: Hua
authors.forename: Stephan
authors.initials: S
authors.lastname: Saikali
authors.forename: Jean François
authors.initials: JF
authors.lastname: Laurent
authors.forename: Daniel
authors.initials: D
authors.lastname: Gedouin
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ben-Hassel
authors.forename: Yvon
authors.initials: Y
authors.lastname: Guegan
mesh_terms: D001927:Brain Diseases / Q000473:pathology / Q000628:therapy; D001932:Brain Neoplasms / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002471:Cell Transformation, Neoplastic; D004814:Epidermal Cyst / Q000473:pathology* / Q000628:therapy; D006801:Humans