Keratocystic odontogenic tumour
|Micrograph of an odontogenic keratocyst. H&E stain.|
|Classification and external resources|
|ICD-10||D16.4 (Maxilla); D16.5 (mandible)|
In the WHO/IARC classification of head and neck pathology, this clinical entity had been known for years as the odontogenic keratocyst; it was reclassified as keratocystic odontogenic tumour (KCOT) from 2005 to 2017. In 2017 it reverted to the earlier name, as the new WHO/IARC classification reclassified OKC back into the cystic category. The WHO/IARC classification no longer considers it a neoplasm, because the evidence supporting that hypothesis (for example, clonality) is considered insufficient. However, this is an area of hot debate within the head and neck pathology community, and some pathologists still regard OKC as a neoplasm despite the reclassification.
Signs and symptoms
KCOTs are thought to arise from the dental lamina and are associated with impacted teeth. Multiple odontogenic keratocysts are a feature of nevoid basal cell carcinoma syndrome. Odotogenic Keratocysts are derived from the remnants of the Dental Lamina.
On a CT scan, The radiodensity of a keratocystic odontogenic tumour is about 30 Hounsfield units, which is about the same as ameloblastomas. Yet, ameloblastomas show more bone expansion and seldom show high density areas.
- Radicular cyst (particularly if the OKC is very inflamed)
- Unicystic ameloblastoma
As the condition is quite rare, opinions among experts about how to treat OKCs differ.
- Wide (local) surgical excision.
- Marsupialization - the surgical opening of the (OKC) cavity and a creation of a marsupial-like pouch, so that the cavity is in contact with the outside for an extended period, e.g. three months.
- Curettage (simple excision & scrape-out of cavity).
- Peripheral ostectomy after curettage and/or enucleation.
- Simple excision.
- Carnoy's solution - usually used in conjunction with excision.
- Enucleation and cryotherapy 
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