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Odontotgenic tumors arise frome odontogebic tissue .

Odontogenic tissue is odontogenic epithelium and odontogenic mesnchyme .odontogenic epitheliume is represented by the enamel organ and you remember the enamel organ which contain columnar cells at the periphery which are the ameloblast and stellaet reticulm at the center .dentine originate from connective tissue (mesenchymel tissue ) because we have reciprocal indaction then dental papilla produce dentine. So we have epithelium and mesenchyme either of these tow component may give rise to tumors. so we have odontogenic tumors which originates completely from epithelial origin and we have odontogenic tumors which originates from mesenchemal origin and we have odontogenic tumors which arise from both epithelial and mesenchymal together this is the bases of calcification of odontogenic tumors .WHO calcification lately2003 changed the name of OKC to keratinizing cystic odontogenic tumor another change to a cyst was call coc (calcifying odontogenic cyst to calcifying cystic odontogenic tumor. These tow cyst has been changed to odonotogenic tumors due to their clinical behavior.

Odontogenic tumors of epithelial origin

Epithelial lesions:

(1) Without odontogenic mesenchyme (epithelial origin)

Ameloblastoma

Squamous odontogenic tumor not included

Calcifying epithelial odontogenic tumor

Adenomatoid odontogenic tumor

Keratinizing cystic odontogenic tumor

Now we have tumors of epithelial and mesenchymal origin :

(2) With odontogenic mesenchyme (mixed epithelial and nesenchymal)

Ameloblastic fibroma and fibrodentinoma

Ameloblastic fibro-odontoma

Odontoamaloblastoma

Calcifying odontogenic cyst and dentinogenic ghost cell tumor

Calcifying cystic odontogenic tumor (calcifying odontogenic cyst) and dentinogenic ghost cell tumor

Complex odontome*

Compound odontome*

According Ameloblastic fibroma and fibrodentinoma here we have fibroma which mean mesenchymal origin and ameloblastic which mean epithelial origin so if we say that ameloplastic fibroma or fibroodontoma is mesenchymal origin or epithelial origin only that is false because its mixed origin . but if we say amelobalstoma alone its epithelial origin ,when we say ameloplastic something its most likely mixed .complex and compound odontoma are of mixed origin because they contain enamel(epithelial ORIGIN) and dentine (mesenchymal origin )…odontoms are surrounded by dental follicles so they contain connective tissue ,there is a debate on the odontoma that its may be considered as hamertomma (normal tissue in normal position but in abnormal organization ).

Mesenchymal lesions

Odontogenic fibroma

Myxoma

Cementoblastoma

NOW WE HAVE TUOMRS OF DEBATEBLE ORIGIN

Melanotic neuroectodermal tumor of infancy

Congenital gingival granular cell tumor) (congenital epulis

Their sources aren’t well known they arise in the jaw according to the melanotic neuroectodermal tuomr of infancy mostly its arise from neuroectoderm .congenital epulis the infant come with a lesion on the gingiva polyop on the gingiva we call it congenital because it arise with the birth of the infant ,and becuse its on the gingival we call it epulis so (congenital epulis)also called granular cell tuomar . Now Dr.saied what do we understand about clacification ? clacification is based on the tissue of origin of the tumor either epithelial alone or mesenchymal alone or mixed.

Now we will start with first lesion which is the most common odontogenic tumor (ameloblastoma)benign

Ameloblastoma : when we have un erupted third molar and if this impactrd 8 has a pericoronal radiolucency so we will consider in our differentiation diagnoses dentogerous cyst ,odontogenic kerato cyst and anyloblastoma .the most common presentation of ameloblastoma is in the posterior region of the mandible with or without association un erupted tooth .the best location is the posterior part of the mandible posterior to the molars it may occurs in the angle or in the ramus of the mandible and if you look at the radiograph

You will see the most likely presentation of amelobastoma which is the multi locular radiographic presentation but it may be unilocular just like dentogerous cyst .so when you find a pericoronal radiolucency try to take biopsy because it maybe ameloblastoma

So ameloblastoma is odontogenic tumor of an epithelial origin most likley occurring in the mandible in the posterior part maybe associated with un erupted tooth or without association of any maybe multi locular or uni locuolar .ameloblastoma extends through the marrow spaces if it occurs in the maxilla it will extend to the maxillary sinus and in the cancellous marrow spaces so it may reach bigger sizes in the maxilla before bone expansion compared to the mandible because it has the whole maxillary sinus to expand in it .but also in the mandible after it spread thorough the marrow spaces it will start causing bony expansion .usually the expansion is fussiy form meaning that it doesn’t have well defined margin and usually egg shell cracking may not occur unless the tumor reaches very big sizes so the perforating of the bone not common .there is a very important feature of ameloblastoma despite its benign its locally invasive as you seen in the radiograph so it needs aggressive treatment it has a high recurrence rate from 50to90 percent high recurrence rate is to due it extention through the marrow spaces ,the tumor extend beyond the safe margins so the surgent cannot remove it completely .less than 1% of oral tumors ,80%in the mandible but it still can be in the maxilla ,majority of the mandible lesions occur posteriorly the majority of maxillary lesions also occur in

posterior areas ,15%involves the ant rum . As it gets larger, there may be gradual facial deformity and bone expansion.

Enlargement is usually bony-hard, non-tender, and ovoid to fusiform.

In advanced cases, egg-shell crackling may be felt due to thinning of cortex.

Perforation of bone and extension into soft tissue are late findings.

the teeth may get lose due to the tumor according to its size but pain is a seldom feature because it doesn’t relly grow fast as it involve the inferior dental nerve or the surrounding nerve so its not like the malignant tumor which grow fast and involve the nerve and metastasize along the nerve ,root resoption may occur un erupted teeth may be associated.

*dentogerous cyst unilocluar *

Ameloblastoma present usually as multilocuolar ,less frequently unilocuolar

Histology of ameloblastoma

Its almost the same of enamel so we have columnar cells at the periphery and stellate reticulum at the center and we are talking about these follicles’ so ameloblastoma is composed of multiple follicles ,follicles composed of epithelial cells ,follicles(epithilum) are the neoplastic component ,each follicle is surrounded be columnar cell which are darker in color nuclei are darker and they are tall and columnar each follicular is composed of columnar cells at the

periphery and stellate reticulum like cell at the center .follicular cells are open up.

Nuclei of peripheral cells are polarized away from the basement membrane. the stroma is fibrocollagenous stroma.

Several change can occure

like cystic changes in the center of the follicles because it may reaching big sizes and the nutrient stope reaching the center of the island and we may have granular cell change in the center meaning the stellate reticulum like cells may have granular or cystic changes or it may start producing keratin (acanthomatus change ,squamous metaplasia).histologicaly there are different patterns but they don’t affect the prognosis of the patient .

there is a different variance of follicular ameloblastoma from the follicular pattern in the plexi form pattern we don’t have big islands or follicles we have strands of epithelial cells and each strands is surrounded by columnar cells with Nuclei of peripheral cells are polarized away from the connective tissue and each strands has a stellate reticulum cells at the center . cystic changes occur in the connective tissue surround the strand in contrast to the follicular

pattern .

origin and pathogenesis of the ameloblastoma

it may be from dental lamina reminant ,lining of the odontogenic cyst either it was dentogerous cyst or okc ,may be from basel cell of oral epithiluim if ameloblastoma is peripheral or may be from odontogenic remnants in the gingival.

Q:peripheral cells why they don’t secret enamel ?because they are consider to be pre ameloblast they are not functioning ameloblastoma

Behavior: its aggressive its locally invasive, shows high recurrence rate up to 90%, it spread through marrow spaces.

*through the oral surgery aspiration of ameloblastoma may occur and it may go to the lunge so later on maybe there ameloblastoma in the lymph node of the lung or in lunge if it not due to aspiration it called malignant ameloblastoma .when we have metastasis regardless if there are cytological changes or not we use the word malignant (malignant ameloblastoma) ,but if we have cytological changes(neoplastic chnges ) regardless if we have metastases or not we use the word carcinoma (ameloblastic carcinoma ) but the most commen is aspiration ameloblastoma .

Ameloblastoma has a small range of polymorphism and of hyperchromatic

Truly malignant ameloblastomas are rare.

Now we have tow sub types of ameloblastoma that should metiond spreately

Unicystic ameloblastoma

suppose we have impacted tooth or any un erupted tooth and there is a big radiolucency around it that maybe cyst or ameloblastoma or odontogenic kerato cyst

Suppose that this was a big cyst and the ameloblastic changes collomuner layer +stellate reticulum layer are only lining the cyst so we call it unicyst ameloblastoma ,they aren’t forming folliculs invading the walls of the cyst

Treatment for the unicystic ameloblastoma

Will be conservative treatment by inoculation while the treatment of ameloblastom is aggressive by block resection and having safe margins

*suppose that the lining of ameloblastoma start to form nodules protruding inside the cyst which we call it neural ameloblastoma and the treatment is the same but when the lining changing invading the tissue of the cyst wall it needs aggressive treatment

So they concider that unicystic ameloblastoma has three histological variance

*the ameloblastoma only lining the cyst

* the ameloblastom is protruding inside the cyst lumen only and these tow are treatment conservatively

*the third variance is that the ameloblastic changes are invading the cyst wall and in this case the treatment is aggressive like the regular ameloblastoma

*the last variance of the ameloblastoma is the peripheral ameloblastoma on the gingival the origin of epithelial is either the basal cells of the oral epithelium or odontogeinc epithelial remnants, its much less invasive its need much less conservative treatment so ,its treated like pyogenic granuloma by exasion

Q:i didn’t hear it but its about cyst ?the answer was based histologicaly on the lining epithelium if we see stellate reticulm cells and basel collomuner layer polorised away from the underlining tissue its ameloblastoma but if we see basel collomuner layer polorised away from the underlining tissue but with uniform thikness and keratin and no stellate reticullm cell its okc if we see only blind epithelial tissue maybe dentogeirous cyst or other types of cyst so the lining epithilum is the bases

Squamous odontogenic tuomr is not included in the exam ????very short essay inthe book

Calcifying epithelial odontogenic tuomrs : calcifying meaning that we have calcifying mineralized tissue epithelial meaning that its from epithelial origin tumour means its a mass no cystic component in the lesion usually ##in the exam if there are 2 true option chose them together.

Calcifying Epithelial Odontogenic Tumor: we use to call it COET

CEOT its odontogenic tumor of epithelial origin >>>what do we know by heart abouth this tumor …

1-it behaves aggressively so it needs aggressive treatment like ameloblastoma

2- It occurs in the posterior part in the mandible this is the best location for the tumor like ameloblastoma

3-it may appear radiographicly completely radiolucent so I may put ameloblastoma in its diffrintional diagnoses or vi versa because at cretin period of time it appears radiolucent but it may also appear mixed radiolucent radio opaque because of this it called calcifying because it may have calcifications .

4- it maybe locally aggressive so its need aggressive treatment and it looks histological aggressive but its benign .

Histological features

Its aggressive but benign ..how do you know its aggressive …when we look at the histological picture of COET will se hyper chromatic cells and there is pleomorphism and we can see varation in the size and shape ,prominent intercellular bridges (spaces between the cells ) it may mismatch with malignat tumors due to this features but its actually benign .what happens in this tumour that the cells secret amyloid like material which may become calcifyid later on and after it calcifyid it will appear radio opaque radiographicly.for this its got the name .these epithelial cells are polyhedral ,eosinophilic cytoplasm ,some of them are paled but most are

deeply eosinophilic bridges are prominent and pleomorphism is a feature but they aren’t malignant .

*it maybe associated with unerupted crowns 50% like ameloblastoma

*it has extraseous variant like peripheral component like ameloblastoma

*its less aggrissve than ameloblastoma

*it may not clearly demarcated like ameloblastoma

*varying amount of radio opaque bodies

Adenomatoid Odontogenic Tumor:

Adenoma mean a benign tumor of epithelial origin …histologically we see gland like structures so we call it adenamatoid but this type of tumor is good because it well defined and treated conservatively ,it occurs in young age ,it occurs anteriorly in the maxilla it’s the best location in association with un erupted tooth , its treated conservativly,it has a extraceous varaient .

Histologicaly :

Its well encapsulated its consist of epithelial cell some cells are spindled and spirling and some of these epithelium cells will form gland like structures these cells are cuboidal or colomuner cells which has epithelial origin they are forming gland like structures ,calcification may occur enamel product may be seen ,there is sheets of polyhedral cells these polyhedral cells show eosiniphilc cytoplasm.,hyperchromatsim .pleomorphism sometimes multinuclation ,they

show pronounced inter cellular bridges ,they don’t have stellate reticulum like cells ,they don’t have cuboidal cells with polarization nuclei a way from the surrounding tissue ,we have amyloid like materials which may be calcified later on ,it doesn’t metastasize ,it’s not malignant ,it’s just locally invasive and destructive but less than ameloblastoma .

Ameloblastic Fibroma:

It has mixed origin ,it has much better prognosis than ameloblastoma ,its treated conservatively not aggressively ,its not invasive ,its occure most frequently in the posterior part of the mandible sometimes in association with un erupted third molar .now if you have an impacted third molar with precoronal radiolucency what are the differential diagnoses?OKC ,dentigerous cyst ,ameloblastoma,CEOT,ameloblastic fibroma.. ….THESE diffirination in case the lesion isn’t multilocular ,recurrent rate is approximately 18% only it mimics dentigerous cyst .

Histologicaly :we should focus on stroma supporting stroma which is fibroblast with high cellularity compared to ameloblastoma for this reason its named ameloblastoma .if you look at the follicles they have the same columnar cells polarized away from the tissue but they are smaller than the follicles in the ameloblastoma ,enamel ,dentine may be formed and when they form it called ameloblastic fibro odontoma(enamel and dentine)or ameloblasic fibro dentinoma (dentin only formed)both same treatment ,

*dental follicals are compose of mysenchemal tissue +remenants of epithelial tissue

*stroma +epithelial =neoplastic .

Calcifying Cystic Odontogenic Tumor (Calcifying Odontogenic Cyst or Gorlin Cyst) & Dentinogenic Ghost Cell Tumor:

Previously it was called Calcifying Odontogenic Cyst but now its called calcifying odontogenic cystic tumor ,it’s also known as gorlin cyst or pind board tumor (not sure of the name ) ….it has a pronounced cystic component if it

hasn’t cystic component bot with same pathological features we call it tumor( Dentinogenic Ghost Cell Tumor)

Dentinogenic ghost cell tumor and calicifyaing odontogenic cyst both have the same histological features but the DGCT dosent have cystic component

Histology:

Both have the same features except the cystic component :now

CCOT .. in the basal layer contain columnar cells with nuclei polarizing a way from the connective tissue and going up we will see stellate reticulum like cells like the ameloblastoma and we said if the cyst was lined with these tow layer we will call it unicystic ameloblastoma but here we don’t have only these tow features we also have ghost cells these are odontogenic cell which gave some cretin changes that will show only the outline if the nucleus this may be a form of apoptosis or cellular changes that’s why it’s called the ghost ,we see pink eosinophilc cytoplasm and outline of the nucleus but we don’t see the nucleus ,these ghost cells may go under calcifications and for this reason it’s called calcifying ,its show ghost cells keretenazation .

Radiographicaly …there will be radioopeaqu mases due to the calcification of the ghost cells

Now spouse that there is no cyst or cavity meaning all the lesion composed of these types of cells we will call it tumor Dentinogenic Ghost Cell Tumor why

Dentinogenic ?because dentine may be formed within the tumor and also dentine with enamel may be formed with in cyst variance .

Odontogenic FibromaClinical Features differences

1-The dentinogenic ghost cell tumor tends to occur in an older age group than the calcifying cystic odontogenic tumor.

2-Both occurs centrly in the jaws but peripheral component may occure BECAUSE WE HAVE ODONTOGENIC REMAMNENTS IN THE GINGIVA AND IN

THE BONE

3-They occure latly in the life 40+

4-They occur anteriorly to molar region in the mandible mostly

5-Maybe associated with un erupted teeth ,may be copletly radiolucens,maybe radiolucenc radio opaque.dependind on the amount of calcification of ghost cells

conservative treatment.for the cystic component but more aggrasseive fore the solid component

mysenchemal tuomrs :

-odontogenic fibroma

-odontogenic myxoma

-cemntoblastoma

What is the difference between fibroma and myxoma ?in the type of fibres if the fibers are collagen dens its fibroma but if they are loose contain high amount of glucose amino glaycan >>gelatinous material >>less fibrous tissues ..its myxoma .

Myxoma goes more in the marrow spaces so its need more aggressive treatment than fibroma ,,,fibroma has better prognosis .

The location of myxom in the mandible posteriorly related to roots or crowns or it may be replace a tooth .origin is from PDL or dental papilla or dental follicle...Dental follicle is the most.

Odontogenic fibroma may occurs in the gingival and it has a peripheral variant called peripheral odontogenic fibroma .

Treatment: by inculcation because its fibrous it doesn’t leak into the marrow spaces ..

*No recurrencs rate in the odontogenic fibroma

*odontogenic tuomr is cellular and contain high amount of fobroblast and cells and contain a remnant of odontogenic epithelial.

*True tumours are cellular

Myxoma is benign but its locally invasive because of the nature of the gelatinous component of the tumour ,its more commen than

odontogenic fibroma ,more in the maxilla. Multilocualr radiolucency,

“soap-bubble”, or tennis-racket” appearance, often with well-defined margins but it’s not always well-defined.

*when we have both dens collagenous and loose golagenouse fiber we call it fibromyxoma or myxofibroma .

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