title: Peripheral odontogenic tumor: a clinicopathologic study of 30 cases. General features and hamartomatous lesions.
abstract: BACKGROUND
  Peripheral odontogenic tumors (POT), either neoplastic or hamartomatous, are rare. This study briefly summarizes the general features of POT and selectively reviews the histomorphologic spectrum of under-recognized hamartomatous lesions that we have designated peripheral odontogenic hamartomas (POH) in order to shed more light into the pathogenesis of POT.
  
  
  METHODS
  Archival material accessioned at our institutions between 1970 and 2004 was systematically searched to identify examples of POT/POH.
  
  
  RESULTS
  Among 39 660 biopsies, we retrieved 25 cases of 'classical' POT and five cases of 'unique' POH. Odontogenic fibroma and ameloblastoma were by far the most common. Of POH, two purely epithelial lesions showed multiple strands of basaloid rests [odontogenic gingival epithelial hamartoma (OGEH)] and a conglomerate of polyhedral epithelium, ghost cells and concentric calcifications (calcifying epithelial odontogenic tumor-like hamartoma), respectively. OGEH and peripheral squamous odontogenic tumor (PSOT) deserve to be a related entity. In two types of mixed POH, ectomesenchymal elements appeared juxtaposed to the squamous lining (gingival cyst-like organoid hamartoma) and ghost cells aggregated in the enamel organ of a microdont (peripheral odontoma). None of POH exhibited continuity with the surface epithelium.
  
  
  CONCLUSIONS
  On the basis of this relatively limited series of cases, POH, to conceptualize a unified histogenetic source, are speculated to arise from the soft-tissue remnants of dental lamina. Gingival rests of Serres seem to retain the ability to pursue epithelial-ectomesenchymal interactions that are necessary leading to odontoma formation.
authors.affiliation: Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan. idef@dent.meikai.ac.jp
authors.forename: F
authors.initials: F
authors.lastname: Ide
authors.forename: K
authors.initials: K
authors.lastname: Obara
authors.forename: K
authors.initials: K
authors.lastname: Mishima
authors.forename: I
authors.initials: I
authors.lastname: Saito
authors.forename: N
authors.initials: N
authors.lastname: Horie
authors.forename: T
authors.initials: T
authors.lastname: Shimoyama
authors.forename: K
authors.initials: K
authors.lastname: Kusama
mesh_terms: D000564:Ameloblastoma / Q000473:pathology; D002114:Calcinosis / Q000473:pathology; D002648:Child; D003560:Cysts / Q000473:pathology; D004475:Ectoderm / Q000473:pathology; D004658:Enamel Organ / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D005260:Female; D005882:Gingival Diseases / Q000145:classification / Q000473:pathology*; D005887:Gingival Neoplasms / Q000145:classification / Q000473:pathology*; D006222:Hamartoma / Q000145:classification / Q000473:pathology*; D006801:Humans; D008297:Male; D008648:Mesoderm / Q000473:pathology; D008875:Middle Aged; D009808:Odontogenic Tumors / Q000145:classification / Q000473:pathology*; D009810:Odontoma / Q000473:pathology