Mandible & maxilla

Odontogenic cysts

Calcifying odontogenic cyst



Topic Completed: 13 August 2021

Minor changes: 13 August 2021

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Cite this page: Bilodeau EA, Hunter KD. Calcifying odontogenic cyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillacalcifyingodontogenic.html. Accessed October 25th, 2021.
Definition / general
  • Benign cyst of odontogenic origin, characterized by an ameloblastoma-like epithelial lining containing ghost cells that may calcify
  • Originally described by Gorlin and colleagues in 1962 as a possible oral analogue to pilomatrixoma of skin, owing to the presence of ghost cell keratinization in both lesions
Essential features
  • Calcifying odontogenic cysts are located most commonly in the anterior regions of jaws
  • Microscopically calcifying odontogenic cysts contain an ameloblastoma-like epithelial lining containing ghost cells that may calcify
  • Calcifying odontogenic cysts are associated with β catenin (CTNNB1) mutations
Terminology
  • Calcifying odontogenic cyst (COC) is the preferred terminology in the 2017 WHO classification
  • Nomenclature has been continuously changing, due to debate as to whether COC is a neoplasm or a developmental cyst
    • In 1992, WHO classified this lesion as an odontogenic tumor but continued to use the term calcifying odontogenic cyst
    • In 2005, WHO redesignated the lesion as calcifying cystic odontogenic tumor (CCOT)
    • In 2017, the term calcifying odontogenic cyst was reapplied to this lesion and it was reclassified as a benign odontogenic cyst
  • Other archaic names include Gorlin cyst and keratinizing and calcifying odontogenic cyst
  • Given the diversity of the histopathologic features seen in COC and its tendency to coexist with other odontogenic lesions, complex classification systems have been proposed (Am J Surg Pathol 2003;27:372, J Oral Pathol Med 2008;37:302, Reichart: Odontogenic Tumors and Allied Lesions, Illustrated Edition, 2004)
  • COC belongs to odontogenic ghost cell family of lesions (J Oral Pathol Med 2008;37:302)
    • From a practical standpoint, a spectrum of histopathologic patterns exists, ranging from a benign lesion that is primarily cystic, a benign lesion with a solid pattern of growth to a rare tumor with features of carcinoma
ICD coding
  • ICD-O: 9301/0 - calcifying odontogenic cyst
  • ICD-10: D16.4 - benign neoplasm of bones of skull and face
  • ICD-10: D16.5 - benign neoplasm of lower jaw bone
Epidemiology
Sites
Pathophysiology
  • Cystic neoplasms with β catenin (CTNNB1) mutations in the Wnt signaling pathway
    • In one series, 91% (10/11) cases of CCOT / COC demonstrated CTNNB1 point mutations COC (PLoS One 2017;12:e0180224)
    • Immunohistochemistry for LEF1 (a transcription factor of the Wnt pathway) is reported to be positive in 64% (7/11) of CCOT (Hum Pathol 2015;46:255)
Clinical features
  • Either asymptomatic (incidental radiographic finding) or a painless swelling
  • Extraosseous lesions present as a gingival swelling, which may be painful
  • May be associated with other odontogenic pathology, most commonly odontoma (J Oral Pathol Med 2018;47:721)
Diagnosis
  • Diagnosis can be made on an incisional biopsy or enucleation specimen
Radiology description
Radiology images

Contributed by Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed.

Coronal CT

Sagittal CT

Axial CT

Prognostic factors
Case reports
Treatment
  • Treated by enucleation and curettage
  • For combined lesions, treat according to characteristics of more aggressive lesion
  • Large cysts may be decompressed prior to surgical management in a 2 stage approach (J Oral Maxillofac Surg 2017;75:1915)
Clinical images

Contributed by Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed.

Extraoral image

Intraoral image

Gross description
  • Unicystic, often 2 cm or less; no solid areas
  • Grossly cystic with focal luminal thickenings
Gross images

Contributed by Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed.

Opened and sectioned cyst

Microscopic (histologic) description
  • Cyst lining is of odontogenic epithelium with a well defined layer of palisading basal cells, loosely arranged suprabasal epithelial cells resembling stellate reticulum, similar to ameloblastoma (microscopic image #1)
    • Unlike ameloblastoma, variable numbers of cells undergo ghost cell change in suprabasilar epithelium (microscopic image #1)
    • Pale, eosinophilic ghost cells are altered epithelial cells with preservation of basic cell outline and eosinophilic cytoplasm but loss of the nucleus; ghost cell change may be due to coagulative necrosis, accumulation of enamel protein, aberrant keratinization of odontogenic epithelium and these cells may calcify (microscopic images #2 - 3)
    • Other variable findings may include:
      • Foreign body giant cell reaction
      • Proliferation of odontogenic epithelium into the cyst wall which can resemble strands of dental lamina (microscopic image #4)
      • Dystrophic calcifications
      • Dentinoid may be laid down next to basal cells:
        • Paucicellular, eosinophilic calcified material considered to represent dysplastic dentin (microscopic image #4)
        • May be present adjacent to epithelial component
        • Most likely formed due to an inductive effect of odontogenic epithelium on adjacent mesenchymal tissue
  • Cyst wall consists of mature fibrous connective tissue containing scattered inflammatory cells (unless secondarily infected)
  • Reference: Reichart: Odontogenic Tumors and Allied Lesions, Illustrated Edition, 2004
Microscopic (histologic) images

Contributed by Elizabeth Ann Bilodeau, D.M.D., M.D., M.S.Ed. and Keith D. Hunter, B.D.S., Ph.D.

Ameloblastomatous lining & ghost cells

Calcification of ghost cells

Island of epithelium with ghost cells

β catenin

LEF1

Cytology description
  • Numerous polyhedral epithelial cells and occasional columnar cells with calcification and Congo red negative extracellular homogenous material in background (Acta Cytol 2009;53:460)
Negative stains
  • Nothing useful or significant
Electron microscopy description
Molecular / cytogenetics description
Sample pathology report
  • Anterior maxilla, right, excisional biopsy:
    • Calcifying odontogenic cyst (calcifying cystic odontogenic tumor) 1.2 cm
Differential diagnosis
Board review style question #1
What is the most common mutation in calcifying odontogenic cyst?

  1. β catenin
  2. BRAF
  3. PPARγ
  4. PTCH
  5. RAS
Board review style answer #1
A. β catenin

Comment Here

Reference: Calcifying odontogenic cyst
Board review style question #2
What odontogenic tumor most commonly is associated with a calcifying odontogenic cyst?

  1. Adamantinomatous craniopharyngioma
  2. Adenomatoid odontogenic tumor
  3. Ameloblastoma
  4. Basal cell adenocarcinoma
  5. Odontoma
Board review style answer #2
Board review style question #3

Which feature is most typical for a calcifying odontogenic cyst?

  1. Cyst lining contains a well defined layer of palisading basal cells and a stellate reticulum-like suprabasal layer
  2. Infiltrative lesion with mitotic activity
  3. No ameloblastic epithelium present
  4. Sellar or suprasellar location
Board review style answer #3
A. Cyst lining contains a well defined layer of palisading basal cells and a stellate reticulum-like suprabasal layer

Comment Here

Reference: Calcifying odontogenic cyst
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