Calcifying odontogenic cyst (Note & Video)
Calcifying odontogenic cyst (COC) was first described by Gorlin in 1962.
It is a cystic lesion characterized histologically by the presence of an ameloblastomatous epithelial lining and ghost cells.
It is thought to arise from the reduced enamel epithelium or the remnants of dental lamina.
There has been much confusion as to whether COC could be a cyst, a tumor or a lesion having cystic and tumor variants.
This lesion was given many different terms --> calcifying cystic odontogenic tumor, calcifying ghost cell odontogenic tumor, dentinogenic ghost cell tumor, calcifying odontogenic lesion and ghost cell cyst.
💡KNOW THY FACTS
- In the 2005 WHO classification, this lesion was termed “Calcifying cystic odontogenic tumor” and was classified as an odontogenic tumor.
- The WHO consensus group in 2017, has reinstated the name “Calcifying odontogenic cyst” and has reclassified the lesion as an odontogenic cyst. The group felt there was sufficient evidence to deem this lesion as a developmental odontogenic cyst.
- “Dentinogenic ghost cell tumor” is considered to be a distinct entity (not a variant of COC). It is classified as an odontogenic tumor.CLINICAL FEATURES
COC is a rare odontogenic cyst and has an equal gender predilection.
This lesion occurs most commonly in persons in the age groups between 20 – 40 years.
COC occurs equally in the maxilla and mandible, but favours the anterior region of the jaws (incisor to canine region).
COC usually presents with a swelling and is mostly asymptomatic.
COC may rarely present as gingival growths (peripheral lesion) resembling fibromas, usually in the incisor-cuspid region.
RADIOLOGY FEATURES
COC usually presents as a unilocular radiolucency and is occasionally multilocular.
Many cases are associated with irregular radiopaque masses within the radiolucencies.
COCs can be associated with odontomas and at least 1/3rd of the lesions are associated with unerupted teeth.
Root resorption and divergence/displacement of teeth is commonly seen.
HISTOPATHOLOGY FEATURES
The epithelial lining resembles that seen in ameloblastoma. It is a palisaded layer of columnar cells and has an overlying layer of stellate reticulum like cells.
Ghost cells are seen in the epithelial lining. They are eosinophilic epithelial cells that lack nuclei or cellular organelles. They may become enlarged or ballooned, fuse with each other and form amorphous sheets of eosinophilic material. Ghost cells may undergo calcification.
There may sometimes be deposits of hyalinised eosinophilic material deposited below the epithelium. This is called dysplastic dentine or dentinoid.
TREATMENT
COC is usually treated conservatively by surgical enucleation.
QUESTIONS? BRING ‘EM ON!!
Is calcifying odontogenic cyst a cyst or a neoplastic cystic tumor?
a)What are ghost cells? b)Are they pathognomonic for calcifying odontogenic cyst?
How is dysplastic dentin or dentinoid formed?
ANSWERS
Refer notes on Tid-Bits - Calcifying Odontogenic Cyst and Ameloblastoma (Note) in the Chapter “Oral Pathology Tid-Bits”.
a) Ghost cells are basically eosinophilic epithelial cells that lack nuclei or cellular organelles. In fact these cells may or may not retain their cellular outline, become enlarged or ballooned, fuse with each other and form amorphous sheets of eosinophilic material.
No one still knows the nature of these cells. While there is a hypothesis that states ghost cells may be a result of abnormal keratinization, there are also theories which propose that these cells may be a phenomenon of coagulative necrosis or abnormal accumulation of enamel proteins. These cells have an affinity for calcification.
b) Ghost cells are characteristic for COC, and not pathognomonic. Ghost cells can be seen in other lesions such as:
Craniopharyngioma
Pilomatricoma
Dentinogenic ghost cell tumor
Odontoma
Ghost cell odontogenic carcinoma
Dysplastic dentin or dentinoid is thought to be dentin like material that arises as a result of an inductive effect of the odontogenic epithelium on the connective tissue cells. This is pretty much like inner enamel epithelium/ameloblasts inducing the dental papilla cells to become odontoblasts, which then secrete dentin.
✅HIGHLIGHTS - VIVA & ENTRANCE EXAM PERSPECTIVE
COC is a cystic lesion characterized histologically by the presence of an ameloblastomatous epithelial lining and ghost cells.
The WHO consensus group in 2017, have reinstated the name “Calcifying odontogenic cyst” and have reclassified the lesion as an odontogenic cyst.
COC occurs frequently in the anterior region of the jaws (incisor to canine region).
Many cases of COCs are associated with irregular radiopaque masses within the radiolucencies.
COCs can be associated with odontomas.
Ghost cells are eosinophilic epithelial cells that lack nuclei or cellular organelles.
Dysplastic dentin or dentinoid is a hyalinised eosinophilic material deposited below the epithelium.
📖REFERENCES AND FURTHER READING
Speight PM, Takata T. New tumour entities in the 4th edition of the World Health Organization Classification of Head and Neck tumours: odontogenic and maxillofacial bone tumours. Virchows Arch. 2018 Mar;472(3):331-339.
Barnes L, Eveson JW, Reichart P, Sidransky D (2005) Odontogenic Tumours. Ch 6, WHO classification of tumors: pathology and genetics of head and neck tumours. IARC, Lyon.
Kramer I, Pindborg J, Shear M (1992) WHO International Histological Classification of Tumours. Histological typing of odontogenic tumours, 2nd edn. Springer-Verlag, Berlin.
Tomich CE. Calcifying odontogenic cyst and dentinogenic ghost cell tumor. Oral Maxillofac Surg Clin North Am. 2004 Aug;16(3):391-7.
Reichart PA, Philipsen HP. Odontogenic tumors and allied lesions. Quintessence Publishing; 2004
Shear M, Speight PM. Cysts of the Oral and Maxillofacial Regions. 4 th ed. Blackwell Munksgaard; 2007.
Neville BW, Damm DD, Allen CM, Chi A. Oral and Maxillofacial Pathology. South Asian ed. Elsevier; 2016.
Rajendran R, Sivapathasundaram B. Shafer’s Textbook of Oral Pathology. 7th ed. Elsevier; 2012.
Regezzi JA, Sciubba JJ, Jordan RCK. Oral Pathology: Clinical Pathologic Correlations. 5 th ed. Elsevier; 2007.