Odontomes and Odontogenic Tumours Flashcards
Define tumour
A swelling or excessive growth of tissue
Not inherently malignant or something dangerous
Define neoplasm
New (neo) growth (plasm) of tissue occurring outside of normal homeostatic mechanisms
May have histologically/cytologically immature or abnormal cells
Define hamartoma
A mass of disorganised tissue native to its normal anatomical location
Histologically mature cells that are arranged in a disorganised manner
Define malignant
A disease process with potential for impairing QoL and life expectancy. Will likely kill the patient if left untreated
Define benign
A disease process with limited potential to impair life expectancy. If left untreated, it is unlikely to kill the patient but could persist/grow to impair QoL
Define odontome
A hamartoma of the tooth forming tissues
An abnormal growth/mass of disorganised tooth forming tissue native to its normal anatomical location
Histologically, the cells that form these tissues will look normal but will be arranged in a disorganised manner
List the 5 types of odontomes
Invaginated odontome
Evaginated odontome
Enamel pearl
Compound odontome
Complex odontome
Briefly describe an invaginated odontome
Abnormal growth of tooth forming tissue. Essentially an infolding of tooth tissue.
Can present as something as simple as a deep cingulum pit. But this pitting process can also be much more severe, resulting in a channel running through the full length of a tooth
The more severe ones are sometimes referred to as a dens in dente, where you get invagination of the tooth tissue to the point where you get a tooth formed inside the tooth. These will have all the normal layers of tooth (enamel, dentine, pulp, cementum) arranged in the correct structural order and relationship to one another
How would you treat an invaginated odontome that has resulted in a superficial cingulum pit?
Treatment will depend on the severity of the invagination and the patient’s ability to maintain OH in the area.
A shallow cingulum pit is unlikely to cause any issues as a PRF or a barrier to OH maintenance in the area, therefore a simple fissure sealant, if suitable could be used to prevent caries
How would you treat an invaginated odontome that has resulted in a very deep cingulum pit?
The treatment will depend on how severe the invagination is.
In the more extreme circumstances, where we get a very deep pit, there is potential for food packing and subsequent decay (due to a combination of the PRF and poor OH in the region - as it would be difficult to clean a deep cingulum pit adequately), we can get a tooth that eventually becomes non-vital.
These teeth may need more destructive intervention or even complete removal, especially if they are abnormally shaped, and therefore do not function properly.
Briefly describe an evaginated odontome
Abnormal growth of tooth forming tissue. Additional tooth forming tissue located on the outside of the crown of a tooth
Can be of varying severity e.g. just a little bit of extra dentine or enamel on the outside of the crown of a tooth or much bigger additions of tooth forming tissues (an additional cusp (talon cusp)
Briefly describe an enamel pearl
Relatively common odontome (abnormal growth of tooth forming tissue)
Formed by the disruption of the enamel follicle which causes it to form a little pearl of enamel, usually at the furcation of a multi-rooted tooth
Where are we most likely to see invaginated or evaginated odontomes?
Invaginated and evaginated odontomes are more common in anterior teeth, as well as maxillary teeth.
Most commonly see them affect the U2s but can be seen in any tooth
Briefly describe a compound odontome
A mass or bag of little teeth
Contains the structural components of a tooth in the correct order (enamel, dentine, pulp, cementum). Has specific areas/parts which resemble the different tooth layers (enamel, dentine, pulp etc.)
Histologically appears much more organised than complex odontomes, with the enamel being laid down on top of the dentine and cementum being laid down the side of it
Radiographically, we will see that the mass is filled with tiny teeth with radiolucent lines that indicate the PDL space and radiolucent centres that indicate the pulp
Briefly describe a complex odontome
A discrete disorganised mass of tooth forming tissue
Contains the structural components of a tooth (enamel, dentine, pulp, cementum) but it doesn’t appear to look like any particular structure as all the structural components are organised in a disordered manner. There is no differentiation between the enamel, dentine and pulpal components
Radiographically, we see a well defined radiopaque mass often with a radiolucent margin around it
Odontomes can occur at any age but which age bracket is most commonly affected by them?
Adolescence
Generally, how are odontomes (especially complex and compound forms) treated?
XLA
Why do complex/compound odontomes need to be removed?
Can impede the eruption of teeth or lead to missing teeth
Can interfere with the orthodontic movement of teeth
How are complex/compound odontomes usually discovered?
Usually found because a tooth hasn’t erupted
Or a tooth is missing
Or as a result of an X-ray taken as part of an orthodontic assessment (as they can interfere with orthodontic movement of teeth)
Briefly describe an ameloblastoma and its features
Tumour (swelling or excessive growth of tissue) that originates from the dental lamina (tooth forming tissue)
Painless, slow growing expansile lesion
Locally aggressive/invasive but metastasis is very rare (not likely to spread to secondary sites and therefore not likely to kill an affected individual although it can significantly impair QoL)
Why does an ameloblastoma need to be treated aggressively?
Recurrence more likely if not treated aggressively
List the non-modifiable risk factors of an ameloblastoma
Ethnicity, 10x more common in Black African people
Age, most commonly affect those in their 40-50s
Describe the radiological features of an ameloblastoma
Most commonly a multilocular radiolucency (can be unilocular), with evident bony expansion and damage to adjacent teeth (resorption).
More commonly seen in the mandible rather than the maxilla and posteriorly rather than anteriorly
How are ameloblastomas classified?
Classified into 3 subtypes-
Follicular (histologically appears organised)
Plexiform (histologically appears quite disorganised)
Unicystic (presents much like a cyst)
Both ameloblastomas and odontogenic keratocysts commonly present as multilocular radiolucenies? What radiological features may help us distinguish between them?
There will be bone expansion in an ameloblastoma whereas a keratocyst doesn’t tend to cause significant bone expansion
Ameloblastomas are also more likely to cause external resorption of associated teeth, whereas odontogenic keratocysts are less likely to do that
How would a plexiform ameloblastoma present?
Slow growing, painless and expansile solid tumour within the bone.
Histologically, will have a disorganised architecture
How would a follicular ameloblastoma present?
Slow growing, painless and expansile solid tumour within the bone.
Histologically, will have an organised architecture
How would a unicystic ameloblastoma present?
Slow growing, painless, expansile lesion that presents like a cyst (well defined, corticated, unilocular radiolucency on a radiograph that may transition to become multilocular later)
If an operation was undertaken to lift a flap, remove the bone and expose the area containing a suspected unicystic ameloblastoma, what are the 3 possible presentations we could find?
Once this area is opened up, we would find a cyst cavity instead of a solid mass of tumour.
If this was sent to a pathologist following removal, the pathologist would find a cyst but in parts of the corner of the cyst, there may be a fond-like appearance with features of an ameloblastoma
OR there may be a solid mass of tumour in one corner
OR even some islands of tumour tissue going off into the stroma deep to the cyst wall lining.
This would be the only way to determine between a cyst and a unicystic ameloblastoma
How can we differentiate between a cyst and a unicystic ameloblastoma
Undertake surgery, lift a flap, remove the bone and expose the area containing the suspected cyst.
Take a biopsy sample to send to a pathologist following removal.
On examination, the pathologist would find a cyst but in parts of the corner of the cyst, there may be a fond-like appearance with features of an ameloblastoma
OR there may be a solid mass of tumour in one corner
OR even some islands of tumour tissue going off into the stroma deep to the cyst wall lining.
This would be the only way to determine between a cyst and a unicystic ameloblastoma.
Briefly describe the management protocol for an ameloblastoma
An ameloblastoma is not a cyst or a hamartoma but it is a locally aggressive neoplasm (benign tumour). The chances of an ameloblastoma recurring if it isn’t treated properly are much higher (++)
Following history taking, examination (E/O, I/O) and special tests (radiographs), if we suspect an ameloblastoma, we need to confirm the diagnosis by taking a biopsy.
Once confirmed, we need to assess the extent of the ameloblastoma using radiographs or CT
Then we need to treat the ameloblastoma with local resection (removal of the tumour with a margin of normal bone on either side)
If the ameloblastoma is particularly large, we may also need to undertake reconstructive surgery following removal
Apart from an ameloblastoma, what other odontogenic tumours can arise in the mouth?
Cementoma
Cemental dysplasia
Cemento-osseous dysplasia
How are PA cysts treated? How likely are they to recur?
Enucleation (removal of the cyst in its entirety)
RCT/XLA of associated tooth
Unlikely to recur if properly treated
How are odontogenic keratocysts treated? How likely are they to recur?
Enculeation with curettage (scraping the bone to make sure we get all the little remnants of cyst lining out) is the gold standard approach.
Can also be treated with marsupialisation
In some cases, a solution called Carnoy’s solution (which fixes the tissues, kills the cells and makes the cyst much easier to remove) can be used
High recurrence rate (+). As keratocysts are multilocular rather than unilocular, it may be a little bit more difficult to get all of the cystic tissue out with enucleation. To add, the cyst lining is very delicate so it is easy to leave a bit of it behind.
What is Carnoy’s solution used for?
Sometimes used to treat an odontogenic keratocyst
Fixes the tissues, kills the cells and makes the cyst much easier to remove
How are oral cancers treated? How likely are they to recur?
Treated using a wide excision with a good margin of normal tissue.
Because it is a cancer (malignant tumour), it has the potential to metastasise so we will also need to start thinking about treating the lymph nodes with either surgery, radiotherapy and possibly chemotherapy.
May need to think about undertaking a reconstruction to reconstruct the primary site following removal as well
Highly likely to recur (+++), if not treated properly
Define cancer
A malignant tumour
Swelling or excessive growth of tissue that has the capacity to impair QoL and life expectancy. If left untreated, the affected individual will likely die
What odontogenic cyst type resembles an ameloblastoma on a radiograph?
Odontogenic keratocyst
What tooth forming tissue is responsible for the formation of an ameloblastoma?
Dental lamina
An ameloblastoma is a ______ ______
A benign tumour (swelling or excessive growth of) the dental lamina (a tooth forming tissue)
