Mandible / maxilla
Fissural and other non-odontogenic cysts
Epidermoid cyst

Author: Annie Morrison, M.D. (see Authors page)
Editor: Kelly R. Magliocca, D.D.S., M.P.H.

Revised: 21 June 2018, last major update April 2015

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Epidermoid cyst [title] jaw

Cite this page: Morrison, A. Fissural and other non-odontogenic cysts: epidermoid cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillaepidermoid.html. Accessed July 22nd, 2018.
Definition / general
  • Cyst lined by stratified squamous epithelium, with orthokeratin production
  • Cyst contents nonspecific and contain keratinaceous, caseous, purulent debris and adjacent cholesterol clefts
Terminology
  • Oral Epidermoid cyst: soft tissue cyst lined by stratified squamous epithelium with orthokeratin layer, without adenexae
    • Often in floor of mouth - remainder of topic focuses on Oral Epidermoid cyst
    • Alveolar and palatal cysts: similar histology to oral epidermoid cyst but in a unique population (newborns) and anatomic site (alveolar ridge or palate)
    • Gnathic epidermoid cysts: not possible to histologically distinguish from orthokeratinized odontongenic cyst (OOC), a cyst typically associated with an impacted tooth
  • Dermoid cyst: lined by stratified squamous epithelium with adnexae (hair follicules, sweat glands, sebaceous glands)
  • Teratoma: can be cystic but must have all three germinal layer represented within cyst wall; ectoderm (skin, hair, teeth), mesoderm (skeletal muscle, vasculature, CNS, peripheral nerves), endoderm (thyroid, GI tract components, lung, liver)
  • Orthokeratinized Odontogenic Cyst: intraosseous odontogenic cyst exhibiting stratified squamous epithelium with orthokeratin
Epidemiology
  • Uncommon
Sites
  • Floor of the mouth
Pathophysiology
  • Congenital inclusion of ectodermal tissue during embryological development
Clinical features
  • Asymptomatic
  • May produce swelling, variable associated pain or visible / palpable defect
Diagnosis
  • Definitive diagnosis reliant on histological examination to rule out other lesions with similar clinical and radiographic appearance
Prognostic factors
  • Benign lesions with low rate of recurrence after excision
Case reports
Treatment
  • Local excision
Clinical images

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Sublingual mass

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Surgical excision

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Cyst

Microscopic (histologic) description
  • Stratified squamous epithelial lining, with granular cell layer
  • No associated adnexal structures (hair, sebaceous glands, etc.)
  • Laminated or flakes of keratin within cyst
Microscopic (histologic) images

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Tissue wall lined by squamous keratinizing epithelium filled with keratin

Differential diagnosis
  • Dermoid cyst: contains cutaneous adnexal structures (sebaceous glands, hair, eccrine sweat glands)
  • Keratocystic odontogenic tumor (formerly odontogenic keratocyst): typically in posterior mandible or mandibular ramus; histologically characterized by stratified squamous lining with parakeratosis and lacking granular cell layer
  • Orthokeratinized odontogenic cyst: intraosseous odontongenic cyst exhibiting stratified squamous epithelium with orthokeratin
    • The hyperchromatic, palisaded nuclei in the basal cell layer so characteristic of KOT, are absent in OOC
  • Residual cyst: following removal of a tooth