Odontogenic Keratocyst (OKC) / Keratocystic Odontogenic Tumour
What is an Odontogenic Keratocyst (OKC)?
The odontogenic keratocyst (OKC) is the most important of the tooth-derived cysts.
This cyst may have any clinical appearance; it is a great mimic and the diagnosis is made after microscopic analysis.
This is the third most common tooth-derived cyst.
These cysts also are found as part of the Basal Cell Nevus Syndrome, also known as Gorlin syndrome.
What are the causes of Odontogenic Keratocysts?
Their cause is controversial.
One theory is that the cyst develops instead of a tooth. Presumably, the cells that would form the tooth undergo cystic degeneration without ever completing tooth formation and develop into the OKC.
The OKC has a number of ‘compartments’ and has connecting smaller cysts that extend into the surrounding bone. Because of this, there is frequent tendency for the condition to recur, particularly if the original surgical treatment did not result in complete removal of the cyst.
Removal of the cyst with removal of surrounding bone and / or cryosurgery (intense cold is applied to the cyst and bone) are the most common forms of treatment.
Long-term follow-up with monitoring by X-ray is important, as if these cysts are left untreated, they can become quite large and locally destructive.
Odontogenic Keratocysts – Key Features
- Usually, multi-locular (many compartments)
- Form intra-osseously (within bone), most frequently in the posterior (back) alveolar ridge or angle of the mandible (lower jaw)
- May grow around a tooth
- Spreads extensively along marrow spaces before expanding into the jaw
- Frequently recurs after enucleation
- Does not respond to marsupialisation
- Definitive diagnosis only by histo-pathology, although clinical & radiographic features may allow fairly accurate pre-operative diagnosis
- May be easily confused with ameloblastoma or, less likely, with dentigerouscysts
- May be part of the jaw cyst / basal cell naevus syndrome