Odontogenic keratocyst
Updates to Article Attributes
Keratocystic odontogenic tumours (KCOT or KOT), previously known as odontogenic keratocysts, are benign cystic neoplasms involving the mandible or maxilla and believed to arise from dental lamina. They are locally aggressive and tend to recur after excision.
On imaging, they typically appear as an expansile solitary unilocular lesion extending longitudinally in the posterior portions of the mandible.
Epidemiology
Present in younger patients (2nd-3rd decades) 1,7, are often multiple, and may be seen in either the body or ramus of the mandible (~70% of all KCOT), or maxilla. There may be male predilection.
Clinical presentation
Commonly discovered incidentally. When symptomatic, jaw swelling and pain are a common clinical presentation of those tumours 8.
Pathology
They originate from epithelial cell rests (stratified squamous keratinizing epithelium) found along the dental lamina and periodontal margin of the alveolus of the mandible 7.
Associations
-
basal cell naevus syndrome (a.k.a. Gorlin-Goltz syndrome)
- multiple KCOT
- strong association
- Marfan syndrome
- Noonan syndrome
Radiographic features
Panoramic radiograph / OPG
Typically seen as a solitary, lucent, unilocular lesion with smooth, corticated borders 5. When in the mandible, they typically grow along the length of the bone in anteroposterior dimension. In the maxilla, they expand into the maxillary sinus (as in Case 2).
They can be associated with a crown of a unerupted/impacted tooth, mimicking a dentigerous cyst. KCOT can result in splaying and sometimes erosion of the adjacent roots.COT COT may occasionally appear septated, making the distinction from ameloblastoma difficult.
MRI
A KCOT will typically demonstrate 3:
- T1: high signal due to cholesterol and keratin contents
- T2: heterogeneous signal
- DWI: restricts due to presence of keratin
-
Post contrast T1T1 C+: peripheral enhancement but unlike ameloblastomas no enhancing nodular component
Treatment and prognosis
They are locally aggressive. Treatment is often with enucleation/excision +/-aggressive curettage. However, they can have a very high recurrence rate (30-60%)
Differential diagnosis
Imaging differential considerations include:
- dentigerous cyst if pericoronal
- ameloblastoma
- calcifying odontogenic cyst (Gorlin cyst) and other odontogenic cysts and tumours
See also
-</ul><h4>Radiographic features</h4><h5>Panoramic radiograph / OPG</h5><p>Typically seen as a solitary, lucent, unilocular lesion with smooth, corticated borders <sup>5</sup>. When in the mandible, they typically grow along the length of the bone in anteroposterior dimension. In the maxilla, they expand into the maxillary sinus (as in Case 2).</p><p>They can be associated with a crown of a unerupted/impacted tooth, mimicking a dentigerous cyst. KCOT can result in splaying and sometimes erosion <span style="line-height:20.8px">of the adjacent roots. </span><span style="line-height:1.6">COT may occasionally appear septated, making the distinction from ameloblastoma difficult. </span></p><h5>MRI</h5><p>A KCOT will typically demonstrate <sup>3</sup>:</p><ul>- +</ul><h4>Radiographic features</h4><h5>Panoramic radiograph / OPG</h5><p>Typically seen as a solitary, lucent, unilocular lesion with smooth, corticated borders <sup>5</sup>. When in the mandible, they typically grow along the length of the bone in anteroposterior dimension. In the maxilla, they expand into the maxillary sinus (as in Case 2).</p><p>They can be associated with a crown of a unerupted/impacted tooth, mimicking a dentigerous cyst. KCOT can result in splaying and sometimes erosion of the adjacent roots. COT may occasionally appear septated, making the distinction from ameloblastoma difficult. </p><h5>MRI</h5><p>A KCOT will typically demonstrate <sup>3</sup>:</p><ul>
-<strong>Post contrast T1: </strong>peripheral enhancement but unlike ameloblastomas no enhancing nodular component</li>- +<strong>T1 C+: </strong>peripheral enhancement but unlike ameloblastomas no enhancing nodular component</li>
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