A keratocystic odontogenic tumour (also keratocystic odontogenic tumor), abbreviated KCOT, is a rare and benign but locally aggressive developmental cystic neoplasm. It most often affects the posterior mandible.
It was previously called odontogenic keratocyst and abbreviated OKC.
The definitive diagnosis is by histologic analysis, i.e. excision and examination under the microscope.
Under the microscope, KCOTs vaguely resemble keratinized squamous epithelium; however, they
- lack rete ridges and
- often have an artifactual separation from their basement membrane.
KCOTs are thought to arise from the dental lamina and 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.
Sporadic (non-syndromic) and syndromic KCOTs are associated with mutations in the gene PTCH, which is part of the Hedgehog signaling pathway.
Swelling is the most common presenting complaint; however, KCOTs may be asymptomatic and found incidentally on dental X-rays.
Malignant transformation to squamous cell carcinoma may occur, but is unusual.
As the entity is quite rare, opinions among experts about how to treat KCOTs differ.
- Wide (local) surgical excision.
- Marsupialization - the surgical opening of the (KCOT) 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).
- Simple excision.
- Carnoy's solution - usually used in conjunction with excision.
- Enucleation and cryotherapy 
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