Mandible & maxilla
Cysts of the jaw
Odontogenic keratocyst
Last author update: 1 December 2013
Last staff update: 28 March 2023
Copyright: 2004-2023, PathologyOutlines.com, Inc.
PubMed Search: Keratocystic odontogenic tumor [title]
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Morrison A. Odontogenic keratocyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillakeratocyst.html. Accessed June 9th, 2023.
Definition / general
- Parakeratin lined cyst-like lesion / tumor within bone
Terminology
- Formerly called keratocystic odontogenic tumor
- The orthokeratinizing odontogenic cyst is considered an unrelated entity without risk of recurrence or aggressive growth or association with Nevoid basal cell carcinoma syndrome
Epidemiology
- 4 - 12% of all odontogenic cysts (often compared to odontogenic cysts even though WHO classifies as tumor)
- Peaks in second and third decade of life, but can occur over wide age range
- 90% are solitary
- Multiple tumors seen in Nevoid Basal Cell Carcinoma Syndrome / Gorlin Syndrome
Sites
- Mandible most commonly involved (65 - 85% of KCOT)
- Most common site: posterior mandible
- Not uncommonly, but not exclusively associated with impacted teeth
- Rarely occurs in soft tissue
Pathophysiology
- Thought to arise from dental lamina
- Two-hit mechanism results in bi-allelic loss of PTCH ("patched") tumor suppressor on 9q22.3-q31 causing dysregulation of p53 and cyclin D1 oncoproteins
- Can occur sporadically or associated with Nevoid Basal Cell Carcinoma Syndrome / Gorlin Syndrome
Clinical features
- Often asymptomatic, incidentally discovered on Xray
- Can cause symptomatic swelling
- Symptoms of pain and drainage if secondarily infected
- Can cause local bone and soft tissue destruction, but usually spares teeth and roots
Diagnosis
- Dependent on radiographic and histopathologic findings
Radiology description
- Small lesions often unilocular radiolucent lesion, variable sclerotic margins
- Larger lesions often multilocular, variable scalloped margins
Radiology images
Images hosted on other servers:
Odontogenic tumor in mandible
Prognostic factors
- Recurrence rates of 20% to 56% with enucleation alone
- Resection is widely reported to have no recurrences, but may be considered excessive for a benign entity
- Multiple lesions can occur when associated with Gorlin Syndrome / Nevoid Basal Cell Carcinoma Syndrome
Case reports
- 54 year old man with 2.5 cm lytic mandibular lesion (Case of the Month #503)
- 74 year old man with a keratocyst in the buccal mucosa with the features of keratocystic odontogenic tumor (Open Dent J 2013;7:152)
- Synchronous occurrence of odontogenic myxoma with multiple keratocystic odontogenic tumors in nevoid basal cell carcinoma syndrome (J Craniofac Surg 2013;24:1840)
Treatment
- Decompression alone
- Enucleation with possible curettage
- Chemical curettage with Carnoy’s solution
- Marsupialization
- Resection
- Treatment must balance minimizing recurrence rate with morbidity associated with an extensive resection
Clinical images
Images hosted on other servers:
Well circumscribed mass
Intraoral finding
Less common maxillary lesion
Gross description
- Thin fibrous wall; usually collapsed; clear fluid or keratinaceous debris if intact
- Unerupted tooth
Gross images
Images hosted on other servers:
Cystic with thin smooth wall
Massive KCOT
Impacted maxillary third molar
Microscopic (histologic) description
- Uniform epithelial lining 6 - 8 cells thick lacking rete ridges
- May have artifactual clefting between epithelium and underlying fibroconnective tissue
- Epithelium characterized by palisaded hyperchromatic basal cell layer comprised of cuboidal to columnar cells
- May have areas of budding growth from the basal cells
- Luminal surface has wavy ("corrugated") parakeratotic epithelial cells
- Lumen may contain keratinaceous debris
- Orthokeratinized variant: orthokeratosis (anuclear keratin), granular layer and poorly organized basal layer; not syndrome associated, less aggressive behavior
Microscopic (histologic) images
Contributed by Kelly Magliocca, D.D.S., M.P.H. & Case #503
Basal layer hyperchromatism
Squamous lined cyst
Areas of inflammation / irritation
Classic microscopic features
Images hosted on other servers:
Various images
Parakeratinized squamous cells
Immunostains
Differential diagnosis
- Radiographic differential:
- Histologic Differential:
- Ameloblastoma with cystic degeneration
- Calcifying odontogenic cyst/Gorlin cyst
- Orthokeratinizing odontogenic cyst
- Unicystic ameloblastoma
Additional references
Board review style question #1
Which of the following sites is most commonly involved in by odontogenic keratocyst?
- Anterior maxilla
- Gingiva
- Mandible
- Maxillary sinus
Board review style answer #1
C. The mandible is most commonly involved site among the anatomic sites listed.
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Reference: Odontogenic keratocyst
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Reference: Odontogenic keratocyst
