title: Orthokeratinized odontogenic cysts presenting as a periapical lesion: report of a case and literature review.
abstract: BACKGROUND
  Inflammatory cysts, granulomas, abscesses, and fibrous scars represent most periapical radiolucencies. However, other less common lesions, such as orthokeratinized odontogenic cysts (OOCs), can be found at this region, and they deserve to be discussed because the prognosis for an OOC is different from that expected for the ordinary inflammatory periapical diseases.
  
  
  METHODS
  An interesting case of OOC associated with a nonvital tooth in a 40-year-old woman is described. After a previous clinical diagnosis of a radicular cyst, the tooth was extracted, and the lesion was enucleated and submitted to microscopy examination.
  
  
  RESULTS
  Because of the detection of an orthokeratinized epithelium lining, a diagnosis of OOC was concluded. After 2 years of periodic follow-up, no signs of recurrence were detected.
  
  
  CONCLUSIONS
  The presence of keratin in radicular lesions must be carefully evaluated to eliminate the diagnosis of lesions with more aggressive behavior, such as an OOC or even a keratocystic odontogenic tumor. Hence, histopathologic examination is mandatory to confirm the type of lesion and to differentiate other pathologic conditions, therefore establishing patients' prognoses precisely.
authors.affiliation: Oral and Maxillofacial Pathology Area, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Silva Servato
authors.affiliation: Oral and Maxillofacial Pathology Area, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Sérgio Vitorino
authors.initials: SV
authors.lastname: Cardoso
authors.affiliation: Department of Oral Surgery, UNITRI-Centro Universitário do Triângulo, Uberlândia, Brazil.
authors.forename: Marcelo Caetano
authors.initials: MC
authors.lastname: Parreira da Silva
authors.affiliation: Department of Oral Surgery, UNITRI-Centro Universitário do Triângulo, Uberlândia, Brazil.
authors.forename: Mirna Scalon
authors.initials: MS
authors.lastname: Cordeiro
authors.affiliation: Department of Morphology, Biomedical Science Institute, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Rogério de Faria
authors.affiliation: Oral and Maxillofacial Pathology Area, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil. Electronic address: adrianol@hc.ufu.br.
authors.forename: Adriano Mota
authors.initials: AM
authors.lastname: Loyola
mesh_terms: D000328:Adult; D003238:Connective Tissue / Q000473:pathology; D003937:Diagnosis, Differential; D004848:Epithelium / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007633:Keratins / Q000032:analysis; D009807:Odontogenic Cysts / Q000175:diagnosis* / Q000473:pathology; D010483:Periapical Diseases / Q000175:diagnosis*; D011842:Radicular Cyst / Q000175:diagnosis; D014081:Tooth Extraction / Q000379:methods; D019553:Tooth, Nonvital / Q000175:diagnosis
chemical_list: D007633:Keratins
keywords: Differential diagnosis; odontogenic cysts; orthokeratinized odontogenic cyst; radicular cyst