Ameloblastoma is a benign but invasive odontogenic tumor that arises from epithelial tooth-forming cells. It most commonly occurs in the mandible of adults between 30-60 years old. Clinically, it presents as a painless swelling and expansion of the jaw. Radiographically, it appears as a multilocular radiolucency. Histologically, it is characterized by proliferating odontogenic epithelium forming follicles. Treatment ranges from conservative curettage to segmental resection depending on the size and location of the tumor. Unicystic ameloblastoma originates within the lining of an odontogenic cyst and has a better prognosis than the conventional type.

1. Ameloblastoma
By:
Mohamed Saber

2. Ameloblastoma
Definition
Etiology
Origin
Types
Clinical features(incidence)
Clinical presentaion
Radiographic presentation
Histopathological findings
Differential diagnosis
treatment

3. It is a benign but invasive epithelial odontogenic
neoplasm.
Consisting of proliferating odontogenic
epithelium lying in fibrous stroma

4. etiology
Unknown , but possible causal factors
suggested :
Truama or inflamation
Oral infection,extraction,injury to teeth or jaws
Irritation resulting from eruption of the third
molar

5. Origin of ameloblastoma
The precise point of origin of ameloblastoma is
unknown ,the origin might be from:
Epithelial rests of serre or malassez
Epithelial lining of non neoplastic odontogenic
cyst(dentigerous cyst)
Direct from oral epithelium

6. types
Conventional solid or multicystic 94%
Unicystic(mural) 5%
Peripheral or extraosseous 1%

7. incidence
It’s the most common epithelial odontogenic
neoplasm.
It comprises about 1% of all oral tumors.
Mandible>maxilla 85%:15%
in mandible:
70% in molar-ramus area, 20%in premolar area,
10% in incisor region

8. incidence
In the maxilla:
Tumor found in the posterior region
Age predilection :
Fourth and fifth decades
The tumor can occur in children or in old age

9. Clinical presentation
In the early stages : ameloblastoma grows slowly
&silently without clinical signs.
in advanced stages:
neoplasm expand cortical plates
thinning of bone (egg shell crackling )erodes
them invades the soft tissue
At this point ameloblastoma present clinically as
a smooth surfaced local expansion of the jaw
producing asymmetry.

10. Clinical presentation
Lesion may be composed of solid tumor,cystic
areas,or booth.
Tipping or loosening of teeth,involvement of inf.
Alveolar nerve may occur.
Draining sinuses,unhealed extraction sockets
associated with granulation tissue within the
socket,bleeding ,trismus& other dental
problems may be the chief complain

11. Clinical presentation
Max. ameloblastoma:
Nasal obstruction is 1st symptoms
Potentially lethal if sinus involved or tumor invade
the bone into soft tissues due to:
Bone is not compact, easily invaded
Proximity to: nasal cavity&sinuses
orbital&pharyngeal tissues
vital structures at base of skull
This factors also complicate comlete removal

14. Radiographic presentation
Ameloblastoma is osteolytic lesion
Unilocular or multilocul radiolucency
Multilocular lesion may be :
Honey combed (small loculation)
Soap bubble (large loculation)
Crtical bone may be spread &expanded or
destroyed.
Unerrupted tooth may be present(resembling
dentigerous cyst)

15. Radiographic presentation
Root resorption of associated teeth.
Maxillary tumors produce a monocystic cavity
in most instances.

21. Histopathological findings
Ameloblastoma can be classified into:
Follicular ameloblastoma or plexiform
ameloblastoma.
Variant s of follicular ameloblastoma:
Cystic type
Basal cell type
Acanthomatous type
Dysmoplasatic type

22. Histopathological findings
Follicular ameloblastoma:
Made of epithelial follicles resembling enamel
organ in mature fibrous c.t. stroma.
Epithelial follicles consist of peripheral tall
columnar cells(ameloblast like cells)& central
core of loosely arranged angular cells (the
stellate reticulaum like cells)

23. Histopathological findings
Plexiform ameloblastoma:
The epithelium is arranged in a network of
anastomosing strands and cords with the
same cell layers as follicular ameloblastoma.

27. Differential diagnosis
Other odontogenic tumors:
Ameloblastic fibroma,odontogenic myxoma.
Non odontogenic tumors:
Central giant cell granuloma,aneurysmal bone
cyst.
Odontogenic cysts:
Dentigerous cyst,odontogenic keratocyst

28. Treatment
Treatment of ameloblastoma ranges from
conservative curettage to radicular resection.
Treatment varies according to
site,size&characteristics of the ameloblastoma
Curettage
En-block resection
Segmental resection

29. curettage
It is the removal of the tumor by scraping it from
the surrounding normal tissue.
It is the least desirable form of therapy.
Failure of curettage is due to extension of tumor
cell nests beyond the clinical& radiographic
margins of the lesion,therefore it is impossible
to eradicate by scraping procedure.

30. En –block resection
It is removal of the tumor with a rim of uninvolved
bone safe margin,but with maintaining the
continuity of the jaw.
It is frequently used for ameloblastoma,although
there is a diffuse invasion of cancellous spaces of
bone marrow by finger like projections,tumor
tissue doesn’t invade the haversian system of
compact bone,thus compact bone of mandible
can be eroded but it is less likely to be invaded.

31. Segmental resection
Segmental resection including
hemimaxillectomy& hemimanibulectomy has
been the most commonly used treatment for
ameloblastoma.
Most authors who advocate this method have
had the least number of recurrence.

36. Unicystic(mural) ameloblastoma
Its formed in the wall of a dentigerous cyst
Its ranked next to dentigerous cyst as the most
frequently occuring pathologic pericoronal
radiolucency.
The terms mural or unicystic are used to identify
this type ,although unicystic ameloblastoma
can occur in other locations &not contacted to
teeth

37. Unicystic(mural) ameloblastoma
It represent about 5% of all ameloblastoma.
The conventional ameloblastoma and mural
ameloblastoma are similar in predilection for
gender(males&females equally affected)&
Site(mand. 3rd molar region)
However the mural variety occur in younger age
gp.(2nd &3rd decades)
Can be related to other types of
cyst(radicular,primordial,residual--
,globulomaxillary)

38. Unicystic(mural) ameloblastoma
in early stage asymptomatic,undetected untile
pericoronal radiolucency is seen on routine
radiograph.
Slowly enlarged,slight non tender sweeling
appear clinically.
If bone destruction occur,palpation discloses
softer areas.

39. Unicystic(mural) ameloblastoma
Radiographically:
If haziness&thinning of hyperostotic
radioopaque rim of pericoronal radiolucency
Tumor invade the capsule of the cyst &start to
infiltrate the bone trabeculae .

42. management
Before undertaking surgical procedure of
pericoronal radiolucency, differential diagnosis
bet. mural(unicystic) &conventional
ameloblastoma should be completed.
At surgery the cyst should be enucleated,and if
mural mass is discovered flag it with suture to
enable the pathologist for further
investigation.

43. management
If pathologist examination establishes the mass
as ameloblastoma that has not penetrated the
basement membrane no further surgery is
done.
If the neoplasm has penetrated the basement
membrane more the bone should be removed
with curettage.
In all cases careful periodic follow- up is always
indicated.

51. Peripheral(extraosseous)
ameloblastoma
Origin: basal layer of oral epith.&extraosseous
portion of epith. Rests of serre.
Site: commonly affect gingiva & alveolar mucosa
mandible> maxilla
Micoscopically it looks like acanthomatous type of
basal cell carcinoma of the skin.
Management: excision.
Behavior: less invasive than intraosseous
ameloblastoma.