title: A clinicopathologic study on calcifying epithelial odontogenic tumor: with special reference to Langerhans cell variant.
abstract: BACKGROUND
  Calcifying epithelial odontogenic tumour (CEOT) is a rare benign odontogenic tumour, and its Langerhans cell variant is even rarer. Due to the limited number of recorded cases, the biological behaviour and histogenesis of the Langerhans cell variant of CEOT are not yet fully understood. Thus, the correlation between conventional CEOT and the Langerhans cell variant remains to be clarified.
  Eight cases of CEOT including 2 cases of Langerhans cell variant were clinicopathologically studied and the English language literature was reviewed. Langerhans cells were detected in 2 cases of conventional CEOT and in 2 cases of Langerhans cell variant by immunohistochemistry.
  
  
  RESULTS
  In the 6 cases of conventional CEOT, 5 tumours involved the premolar and molar region and the anterior portion of the mandible was affected in 1 case. Four patients were followed for 2-7 years and did not show any sign of recurrence. A review of the English language literature revealed 5 cases; combined with the present 2 new cases, a total of 7 cases of Langerhans cell variant of CEOT were collected. The patients were all Asian. Six tumours occurred in the maxilla and 1 in mandible; all mainly involved the anterior region of the jaws. Five patients were followed for 2-10 years and did not show any evidence of recurrence. Langerhans cells can be seen in both the conventional and the Langerhans cell variant of CEOT; however, increased numbers of Langerhans cells are seen in the latter.
  
  
  CONCLUSIONS
  Although the Langerhans cell variant of CEOT is a rare entity and behaves similarly to the conventional type, it could show unique clinical and histologic features that may pose problems for differential diagnosis.
  http://www.diagnosticpathology.diagnomx.eu/vs/1979090740113894.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China. litiejun22@vip.sina.com.
authors.forename: Tie-Jun
authors.initials: TJ
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D007801:Langerhans Cells / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009808:Odontogenic Tumors / Q000473:pathology*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology*; D055815:Young Adult