title: Orthokeratinized odontogenic cyst: a clinicopathologic study of 61 cases.
abstract: BACKGROUND
  Orthokeratinized odontogenic cyst (OOC) is a relatively uncommon developmental cyst comprising about 10% of cases that had been previously coded as odontogenic keratocysts. Odontogenic keratocyst was designated as keratocystic odontogenic tumor (KCOT) in the new World Health Organization classification and OOC should be distinguished from KCOT for differences in histologic features and biologic behavior.
  
  
  OBJECTIVE
  To analyze the clinicopathologic features of 61 cases of OOC in a Chinese population.
  
  
  METHODS
  Clinicopathologic analysis was performed on 61 cases of OOC. Immunohistochemical expression of Ki-67 and p63 was evaluated in 15 OOCs and 15 typical KCOTs.
  
  
  RESULTS
  The 61 patients with OOC ranged from 13 to 75 years (average, 38.93 years). The lesions developed mainly in the third and fourth decades (57.38%) with a distinct predilection for males (72.13%). Six (9.84%) lesions were found in the maxilla and 55 (90.16%) in the mandible. The most common sites were in the mandibular molar and ramus region. Of the 54 cases with radiographic record, 47 (87.04%) were unilocular and 7 (12.96%) were multilocular radiolucencies. Twenty-seven of the 54 cysts were associated with an impacted tooth. Follow-up of 42 patients revealed no recurrence during an average period of 76.8 months after surgery. Compared with KCOTs, expression level of Ki-67 and p63 was significantly lower in OOCs, suggesting a lower proliferative activity.
  
  
  CONCLUSIONS
  Orthokeratinized odontogenic cyst is clinicopathologically distinct from KCOT and should constitute its own clinical entity.
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Peking University, Beijing 100081, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Dong
authors.forename: Shuang
authors.initials: S
authors.lastname: Pan
authors.forename: Li-Sha
authors.initials: LS
authors.lastname: Sun
authors.forename: Tie-Jun
authors.initials: TJ
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008875:Middle Aged; D009807:Odontogenic Cysts / Q000473:pathology* / Q000601:surgery
chemical_list: C081876:CKAP4 protein, human; D019394:Ki-67 Antigen; D008565:Membrane Proteins