Mandible & maxilla
Non-odontogenic cysts within bone and oral mucosa/oral cavity
Epidermoid cyst
Topic Completed: 1 April 2015
Minor changes: 8 July 2020
Copyright: 2004-2019, PathologyOutlines.com, Inc.
PubMed Search: Epidermoid cyst [title] jaw
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Diagnosis | Prognostic factors | Case reports | Treatment | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosisCite this page: Morrison A. Epidermoid cyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillaepidermoid.html. Accessed August 7th, 2020.
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
- The hyperchromatic, palisaded nuclei in basal cell layer, characteristic of Keratocystic Odontogenic Tumor, are absent in OOC
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
- 26 year old woman with epidermoid cyst of floor of mouth (Natl J Maxillofac Surg 2014;5:79)
Treatment
- Local excision
Clinical images
Images hosted on other servers:
Sublingual mass
Surgical excision
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
Images hosted on other servers:
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
