title: Primordial odontogenic tumour: clinicopathological analysis of six cases of a previously undescribed entity.
abstract: OBJECTIVE
  To describe the clinicopathological and immuno-histochemical features of six tumours that do not fulfil the criteria of any of the currently classified odontogenic tumours.
  
  
  RESULTS
  The patients were three males and three females, whose ages ranged from 3 years to 18 years (mean, 11.05 years). In all cases there were well-defined radiolucencies associated with unerupted teeth apparently showing a pericoronal relationship. Microscopically, all tumours were composed of variably cellular loose fibrous tissue with areas similar to dental papilla, entirely surrounded by cuboidal to columnar epithelium resembling the internal epithelium of the enamel organ. Mesenchymal tissue was positive only for vimentin, and Ki67 expression was very low (<2%). The epithelium was positive for CK AE1/AE3, CK5, CK14, and CK19, but negative for CK18 and CK20. All cases showed clear demarcation from the surrounding bone, and were surgically removed, with no recurrences after follow-up ranging from 6 months to 20 years.
  
  
  CONCLUSIONS
  These findings differ from those observed in other odontogenic lesions, such as ameloblastic fibroma, odontogenic myxoma, odontogenic fibroma, and hyperplastic dental follicles. The term primordial odontogenic tumour is proposed to describe this novel lesion.
authors.affiliation: Departamento de Atención a la Salud, Universidad Autónoma Metropolitana Xochimilco, México DF, México.
authors.forename: Adalberto
authors.initials: A
authors.lastname: Mosqueda-Taylor
authors.forename: Fabio Ramoa
authors.initials: FR
authors.lastname: Pires
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Aguirre-Urízar
authors.forename: Roman
authors.initials: R
authors.lastname: Carlos-Bregni
authors.forename: José Mario
authors.initials: JM
authors.lastname: de la Piedra-Garza
authors.forename: Rafael
authors.initials: R
authors.lastname: Martínez-Conde
authors.forename: Guillermo
authors.initials: G
authors.lastname: Martínez-Mata
authors.forename: Sergio J
authors.initials: SJ
authors.lastname: Carreño-Álvarez
authors.forename: Henrique Martins
authors.initials: HM
authors.lastname: da Silveira
authors.forename: Bruno Santos
authors.initials: BS
authors.lastname: de Barros Dias
authors.forename: Oslei Paes
authors.initials: OP
authors.lastname: de Almeida
mesh_terms: D000293:Adolescent; D014408:Biomarkers, Tumor / Q000378:metabolism*; D004848:Epithelium / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007573:Jaw Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D008297:Male; D009808:Odontogenic Tumors / Q000145:classification* / Q000378:metabolism / Q000473:pathology / Q000628:therapy
chemical_list: D014408:Biomarkers, Tumor
keywords: dental follicle; dental papilla; jaws; odontogenic tumour; tooth primordium