title: Peripheral odontogenic keratocyst.
abstract: BACKGROUND
  An odontogenic keratocyst can develop at virtually any site in the jaws and is of concern because of its aggressive clinical behavior. It represents 3% to 12% of all odontogenic cysts. This paper describes the rare peripheral presentation of an odontogenic keratocyst localized to the maxillary anterior gingiva and its differential diagnosis.
  
  
  METHODS
  A patient presented with a round yellow nodule on the maxillary gingiva between the left canine and first premolar. Clinical examination ruled out periapical abscess, periodontal abscess, and lateral periodontal cyst. A differential diagnosis included a gingival cyst, neuroma, neurilemoma, and mesenchymoma. The cyst ruptured during excisional biopsy revealing contents typical of an odontogenic keratocyst (OKC). Histology confirmed the peripheral OKC diagnosis. A conservative surgical treatment was performed assuming a less aggressive clinical course for the peripheral odontogenic keratocyst. Close follow-up was planned.
  
  
  RESULTS
  To our knowledge, only 13 cases of peripheral OKC have been reported in the literature. Presently it is unknown if the peripheral variant shares the aggressive clinical behavior and recurrence rate of intraosseous OKC.
  
  
  CONCLUSIONS
  This paper may contribute to the limited clinical knowledge base for the peripheral odontogenic keratocyst and assist clinicians in the identification and management of such lesions.
authors.affiliation: Postgraduate Periodontics Program, College of Dentistry, University of Nebraska Medical Center, Lincoln, NE 68583-0740, USA. rpreston@unmc.edu
authors.forename: Rhonda D
authors.initials: RD
authors.lastname: Preston
authors.forename: Nagamani
authors.initials: N
authors.lastname: Narayana
mesh_terms: D000369:Aged, 80 and over; D001706:Biopsy; D003560:Cysts / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D005882:Gingival Diseases / Q000175:diagnosis; D006801:Humans; D008439:Maxillary Diseases / Q000473:pathology*; D008637:Mesenchymoma / Q000175:diagnosis; D009442:Neurilemmoma / Q000175:diagnosis; D009463:Neuroma / Q000175:diagnosis; D009807:Odontogenic Cysts / Q000473:pathology*; D010482:Periapical Abscess / Q000175:diagnosis