title: International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma.
abstract: BACKGROUND
  Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC).
  
  
  METHODS
  The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines.
  
  
  RESULTS
  CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included.
  
  
  CONCLUSIONS
  Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.
authors.affiliation: Oral Pathology Department, Facultad de Odontología, Universidad Nacional Autónoma de México, México, DF, México. cledezma@servidor.unam.mx
authors.forename: Constantino
authors.initials: C
authors.lastname: Ledesma-Montes
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gorlin
authors.forename: Mervyn
authors.initials: M
authors.lastname: Shear
authors.forename: Finn
authors.initials: F
authors.lastname: Prae Torius
authors.forename: Adalberto
authors.initials: A
authors.lastname: Mosqueda-Taylor
authors.forename: Mario
authors.initials: M
authors.lastname: Altini
authors.forename: Krishnan
authors.initials: K
authors.lastname: Unni
authors.forename: Oslei
authors.initials: O
authors.lastname: Paes de Almeida
authors.forename: Román
authors.initials: R
authors.lastname: Carlos-Bregni
authors.forename: Elías
authors.initials: E
authors.lastname: Romero de León
authors.forename: Vince
authors.initials: V
authors.lastname: Phillips
authors.forename: Wilson
authors.initials: W
authors.lastname: Delgado-Azañero
authors.forename: Abelardo
authors.initials: A
authors.lastname: Meneses-García
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002471:Cell Transformation, Neoplastic; D002648:Child; D005260:Female; D006801:Humans; D007391:International Cooperation; D007573:Jaw Neoplasms / Q000145:classification* / Q000150:complications / Q000473:pathology*; D007633:Keratins; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018333:Odontogenic Cyst, Calcifying / Q000145:classification* / Q000150:complications / Q000473:pathology*; D009808:Odontogenic Tumors / Q000145:classification* / Q000150:complications / Q000473:pathology*; D012189:Retrospective Studies; D017678:Sex Distribution; D014097:Tooth, Unerupted / Q000150:complications
chemical_list: D007633:Keratins