4. Odontogenic Bone Tumors Flashcards
Traumatic bone cyst
Now that lesion is NOT going to cause resorption of the ____, not going to cause displacement of the teeth and certainly will not cause ____ of the bone.
• It is strictly an intraosseous condition that is the result of a ____ within the jaw bone or any bone for that matter, that while that resolved the bone itself did not heal around it and that is why radiographically it still appears lucent, but it won’t cause any other disturbances to the ____ or to the teeth around it.
roots
expansive
hematoma
bone
Odontogenic tumors
Derived from ____, ectomesenchymal and/or ____ elements of tooth-forming apparatus
• Or ____ tissue which is the mesenchymal tissue found in ____ during development or any combination thereof
epithelial
mesenchymal
ecto-mesenchymal
neural crest
Odontogenic ____ with mature, fibrous stroma without odontogenic ectomesenchyme
Ameloblastoma, solid/multicystic type Ameloblastoma, extraosseous/peripheral type
Ameloblastoma, desmoplastic type Ameloblastoma, unicystic type
Calcifying epithelial odontogenic tumor Adenomatoid odontogenic tumor Keratocystic odontogenic tumor
Beginning with the most common subset of tumor which are epithelial in origin. These tumors whereby the
tumor cells are epithelial in nature, not mesenchymal, not ecto-mesenchymal.
• The most common of these is ____. We will go thru the categories and we have already gone over ____ at the end.
• This is based on the previous WHO description whereby they include OKC in this category of epithelial
____. In the current update, it is still there but it is there with a question mark as to whether it truly is a tumor but none the less I have characterized it as an epithelial proliferation
epithelium
ameloblastoma
OKC
neoplastic
Odontogenic epithelium with odontogenic ____ with or without hard tissue formation
Calcifying cystic odontogenic tumor
Ameloblastic fibroma Ameloblastic fibro-odontoma
Odontoma, complex type Odontoma, compound type
The second category are tumors composed of epithelium and mesenchymal tissue where both components are neoplastic the epithelium component and ____ component.
ectomesenchyme
mesenchymal
Mesenchyme and/or odontogenic ectomesenchyme with or without odontogenic ____
Odontogenic myxoma Cementoblastoma
The last group, which are much more limited in scope in terms of different neoplasia.
• These are tumors derived from neoplasia of ____ or mesenchymal cells and NOT epithelial cells.
• They may contain epithelium, but the epithelium contained is not ____.
• The epithelium is some ____ or carrier-type tissue(idk what he is referring to?). What is causing the
tumor is the ____ that has become neoplastic. There are two within this category that we will discuss (indicated below). We will primarily discuss epithelium tumors
epithelium
fibroblasts
neoplastic
reactive
fibroblast
Ameloblastoma
most common ____ tumor
____ > 80-90%
– includes ____ variant
unicystic > 10-15%
____ > < 1%
The most common type of epithelial tumor
This is the most common benign jaw bone tumor that we see in clinical practice
It is seen in one of three histologic shapes: either a ____ tumor, a ____ tumor or a tumor that occurs only within the soft tissue, in this case as a ____ tumor
Most commonly in the solid form also called conventional or multi-cystic is found in the jaw bone as unilocular or ____ lucency and always as a ____ (this is an important distinction because some of these mixed tumors are mixed radiographically.) These tumors are always radiolucent.
odontogenic
conventional/multicystic
desmoplastic
peripheral
solid
unicystic
peripheral
multilocular
lucency
Ameloblastoma
The unicystic form is always and only ____ where as conventional is maybe unilocular or ____ radiographically, unicystic is always unilocular, by definition, radiographically and unicystic is always a cystic tumor. It takes the shape of a cyst, microscopically, except the cyst- lining is a tumor-lining/____-lining
Lastly, peripheral ameloblastoma is strictly within the ____ tissue and in this case, that is soft tissue only of the ____ because you don’t get tooth development in the buccal mucosa or tongue so where the teeth develop is where these tumor will occur either within the jaws or gingiva, but radiographically the conventional tumors or unicystic tumors may look like ____ in that they may be beneath teeth, around teeth, in between teeth, away from teeth much like OKC. In this image here, this is a multilocular lesion (arrow) between these two teeth here What are you thinking, first and foremost?____….. Except in this case this was an ameloblastoma. I showed you a case before when I showed you OKC of a very similar lesion that was an OKC.
These warrant a ____ for diagnosis because the treatment for BOC is very different from ameloblastoma. The treatment for this ameloblastoma is required removal of this ____ tooth and the tissue in between, that is a true tumor and that can potentially be an aggressive tumor.
unilocular
multilocular
neoplastic
soft
gingiva
anything
BOC
biopsy
two
Ameloblastoma
____, locally aggressive tumor
____ / unilocular radiolucency May be associated with ____ tooth
• These are benign but locally aggressive tumors
• These can cause local destruction and local invasive into adjacent structures, so maxillary tumors can be
quite debilitating as they can directly extend into the ____.
So going back to the yellow text listed at the bottom of that slide about with dentigerous cysts: Dentigerous cysts are NOT radiographical diagnosis, they are part of the differential because OKCs and ameloblastomas commonly manifest around crowns of ____ teeth.
So if you have a lesion around the crown of an impacted tooth, you are typically thinking those 3 lesions for differential diagnosis: ____, ____ and ____
benign
multilocular
impacted
orbit impacted OKC ameloblastoma dentigerous cyst
Ameloblastoma
So these can be quite extensive.
• This is a massive lesion in the mandible.
• This goes up to coronoid process all the way down to body.
• This is not that dissimilar to the OKC I showed you before, except that patient had massive expansion of
this mandible. So this is the same patient you see radiographically, whereas in the OKC case, that patient had almost no evidence of anything ____ beyond the radiographic presentation.
Can OKCs look like this? They can, very rarely. So in this case, my best guess diagnosis would be ____ in this case and NOT OKC.
clinically
ameloblastoma
Ameloblastoma
So this is the same image from the first slide, I showed you
This is a ____ lucency, this is like soap bubbles (green arrow, he mentioned this earlier)
Image on the right, a lesion between two teeth causing ____ of the roo
multilocular
displacement
Molecular genetics of odontogenicneoplasia
• Mice expressing ____-G12V transgene developed odontogenic tumors
HRAS, KRAS and NRAS
- ____
- promote ____
- suppress apoptosis
- modulate ____ microenvironment, stimulate ____
- enhance metabolism
- immune ____
These are true tumors & these tumors harbor mutations that are characteristic of them.
• In particular, these tumors harbor a mutation one of 3 or more genes.
• Most of the proteins these tumors harbor mutations in are all part of the same ____. Back
in the early 1990’s they were studying a form of lung cancer in mice.
• Back then they already knew some cancers expression HRAS. HRAS is an oncogene that is mutated and
this mutation called G12V (glycine-12) is oncogenic in that tumor. They created mice to overexpress the same oncogene to see where these tumors develop beyond the lung and unexpectedly, they found these mice developed tiny jaw tumors. At that point they did not characterize them further except to say they are jaw tumors, subsequently they looked and found they were ameloblastomas
HRAS plasma membrane GTPases proliferation cellular angiogenesis evasion
molecular pathway
Molecular genetics of ameloblastoma
• Beyond that these same tumors also harbor other mutations one of which is in the same pathways as HRAS, NRAS and KRAS and that protein being BRAF which we are familiar with. ____ mutations have been seen in melanomas and lung cancer.
• BRAF mutations have been seen in a pretty significant subset of ameloblastomas as well and primarily in those tumors that found in the ____.
• Maxillary ameloblastomas do not harbor mutations in BRAF but rather mutations called ____.
• This is interesting because it is the same tumor but in the maxilla they harbor one type of mutation and
in the mandible they harbor another type of mutation. ____ is not in the pathway that HRAS, NRAS or even BRAF is found in, but found in a whole different pathway. We do not know how those tumors develop, we just know that the mutation is found in a good subset of maxillary ameloblastomas
BRAF
mandible
SMO
SMO
BRAF is not associated with cancer in the jaw bone but rather it is associated with ameloblastoma which is a ____ tumor.
benign
Histologic variants
- ____
- Plexiform
- ____
- Granular cell
- ____
- Basal cell
- ____ epithelial cells (ameloblasts)
- Reversed nuclear polarity
- Subnuclear ____
- Stellate-shaped cells (stellate reticulum)
follicular acanthomatous desmoplastic columnar vacuolization
FOLLICULAR VARIANT
You should see 2 things:
• Periphery of tumor islands (here outlined is one distinct tumor island – outlined in green arrows)
• Around the periphery of the island, you should see ____ cells with palisading nuclei. These nuclei are
____ polarized away from the basal membrane (this essentially means the nuclei is pushed away from
the basal membrane and the nuclei are arranged in a palisading pattern)
• Between the nucleus and basal membrane you have a clear ____ in which, under normal circumstances,
these cells would be producing ____ (the same cells which give rise to enamel), except in this context they are neoplastic
These cells look like/mimic ameloblasts histologically, but do not function like ameloblasts (hence the term ameloblastoma). They do not produce ____ and are neoplastic. The dark cells seen in purple are the ameloblasts
Internally, within the tumor island you something called ____ (listed in last line on previous slide). Stellate reticulum is tissue found during normal tooth development.
Ameloblastoma is reproducing structures formed during normal tooth development, except in a neoplastic manner
So the follicular form is islands/small packets with all these features in each packet
columnar cells
reversibly
vacuole
enamel
enamel
stellate reticulum
PLEXIFORM VARIANT
Plexiform appearance is the same features except they go all over the ____. One ____ proliferation of tumor. he points out in the image on the left that there are cords & strands of interconnected tumor cells, that is the plexiform subtype
They are not discrete tumor islands, but rather one long strand of interconnected tumor that is going all over the place
place
continuous
Acanthomatous ameloblastoma is characterized by ____ of the stellate reticulum
Metaplasia is conversion of one normal cell type to another
Now, these aren’t normal cells but what is happening is that the stellate reticulum is being converted to squamous cells so you get acanthomatous change, squamous cell change of the islands. So if you see a cell that has mostly squamous metaplasia we call it acanthomatous variant
sqaumous metaplasia
Then we have granular cell variant
recall what a granular cell tumor is > tumor cells have a ____ appearance
These cells in the image on the right have a very grainy/sandy appearance like what you would see in a granular cell tumor so, in this context, they are called granular cell ameloblastoma
grainy
DESMOPLASTIC VARIANT
• The basal cell variant is pretty rare, so we are not discussing that
• This variant shown is not as rare
• This variant of the tumor has a distinctive radiographic presentation beyond the histology
• It is called desmoplastic ameloblastoma because all the ____ stuff represents the tumor islands
(follicular islands), around it (the pink stuff) is dense ____ so you have dense ____ of the connective tissue hence desmoplastic ameloblastoma
dark/purple
collagen
fibrosis
DESMOPLASTIC VARIANT
This version of the tumor may have a very distinctive radiographic presentation as well
You may see ____ or multi-locular type lucency or you may see as you do in the image on the left below, more of an ill-defined, poorly-defined, almost a mixed appearance radiographically where it is not really radiolucent and not really radiopaque, it has an in between presentation.
Image on the left: it is not really radiolucent, it is not completely dark as it was in some of the other cases, it has an in between appearance. This is sometimes called a ____ appearance, radiographically this is sometimes called a ____ appearance or a mixed type description
ground-glass
mixed
