title: Central odontogenic fibroma: new findings and report of a multicentric collaborative study.
abstract: OBJECTIVE
  The aim of this study was to describe the clinicopathologic and immunohistochemical characteristics of 14 cases of central odontogenic fibroma (COF), and the ultrastructural features of 2 of them.
  
  
  METHODS
  Collaborative retrospective study based on the records of 4 oral pathology diagnostic services in Latin America based on the current World Health Organization classification.
  
  
  RESULTS
  There were 7 male and 7 female patients (mean age 31.8 years). Eight tumors occurred in the maxilla and 6 in the mandible. Thirteen cases were epithelium-rich and 1 epithelium-poor COF. Three were classified as hybrid COF with giant cell lesion. Mean size of the hybrid lesions were larger than pure COF (3.8 vs. 2.4 cm). Odontogenic epithelial islands were immunoreactive for cytokeratin (CK) AE1/AE3, CK5, CK14, CK19, and 34BE12 and negative for CK1 and CK18. Langerhans cells positive for S-100 and CD1a were found within the epithelial islands in 6/6 tested cases. CD68 was expressed in the giant cells of the hybrid lesions and in a few mononuclear cells of 2 cases of COF. Ki-67 index was <1% in all cases. In 6 tumors (42.8%), there were small globular eosinophilic droplets within the epithelial islands, which were positive for collagen type IV, and 9/13 cases (69.2%) were focally positive for smooth muscle actin. In addition to fibroblasts, myofibroblastic differentiation was found in the 2 cases studied ultrastructurally.
  
  
  CONCLUSIONS
  Immunohistochemistry was useful to confirm the presence of epithelium and to exclude other central fibrous tumors. COF also contains a variable number of mast cells, Langerhans cells, and myofibroblasts, and further studies are needed to better understand the participation of these cells in COF histogenesis.
authors.affiliation: Oral Pathology and Medicine, Departamento de Atención la Salud, Universidad Autónoma Metropolitana, Mexico City, Mexico. mosqueda@correo.xoc.uam.mx
authors.forename: Adalberto
authors.initials: A
authors.lastname: Mosqueda-Taylor
authors.forename: Guillermo
authors.initials: G
authors.lastname: Martínez-Mata
authors.forename: Roman
authors.initials: R
authors.lastname: Carlos-Bregni
authors.forename: Pablo Agustin
authors.initials: PA
authors.lastname: Vargas
authors.forename: Victor
authors.initials: V
authors.lastname: Toral-Rizo
authors.forename: Ana María
authors.initials: AM
authors.lastname: Cano-Valdéz
authors.forename: José Mario
authors.initials: JM
authors.lastname: Palma-Guzmán
authors.forename: Daniel
authors.initials: D
authors.lastname: Carrasco-Daza
authors.forename: Kuauhyama
authors.initials: K
authors.lastname: Luna-Ortiz
authors.forename: Constantino
authors.initials: C
authors.lastname: Ledesma-Montes
authors.forename: Oslei Paes
authors.initials: OP
authors.lastname: de Almeida
mesh_terms: D000293:Adolescent; D000328:Adult; D004848:Epithelium / Q000473:pathology; D005260:Female; D005350:Fibroma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000145:classification / Q000378:metabolism*; D008297:Male; D008339:Mandibular Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D008441:Maxillary Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D009808:Odontogenic Tumors / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D007633:Keratins