2. Definition of Odontogenic Tumors
• Tumor:
- The word tumor means swelling.
• Odontogenic tumor:
- A group of neoplasm & tumors-like
malformations arising from cells of
odontogenic apparatus & their remnants.
- In other words, odontogenic tumors arise
from odontogenic tissues.
3. The Origin of Odontogenic Tumors
(Odontogenic Tissues)
Ectodermal Mesenchymal
(epithelium) (C.T)
Dental Lamina +
Dental Papilla.
(Epith. Rests of Serres)
Enamel Organ+
Dental Sac.
(Reduced Enamel Epith.)
Epith. Root Sheath of
Hertwig’s +
(Epith. Rests of Malassez)
5. Classification of Odontogenic Tumors
From O.Epith
From O. From
+
Epith. O.Mesenchyme
Mesenchyme
Ameloblastic Odontogenic
Ameloblastoma
Fibroma Fibroma.
(CEOT) Odontogenic
Odontoma
(Pindborg T) Myxoma.
Adenomatoid O.T
(AOT)
6. Origin of Ameloblastoma
Several origins have been suggested:
• Dental Lamina + its remnants( epith.
Rests of Serres).
• Enamel organ + its remnants ( reduced
enamel epith.).
• Epith. Lining of Dentigerous cyst.
• Basal layer of the oral mucosa.
7. Types of Ameloblastoma
• 1- Simple, Solid,(Multicystic
Ameloblastoma), with its histological variants:
-Follicular A.
-Plexiform A.
• 2-(Unicystic Ameloblastoma), with its
histological variants:
-Luminal Unicystic A.
-Intraluminal Unicystic A.
-Mural Unicystic A.
• 3-Peripheral (S.T) ameloblastoma.
• 4-Desmoplastic ameloblastoma.
8. Solid, Multicystic Ameloblastoma
• Def.:
- It is a benign but locally invasive neoplasm
consisting of epithelium lying in a fibrous
stroma.
- It is one of the few neoplasms that arise from
odontogenic epith.
- It has ↑ recurrence rate than other types of
Ameloblastoma.
9. Clinical Features of Multicystic
Ameloblastoma
• Age: 4th- 5th decade.
• Sex: male = female.
• Race: ↑ in African.
• Site: ↑mand. Molar
area.
• Signs & symptoms:
-painless
-Slowly growing.
-gradula facial asymmetry.
-Looseness of teeth.
-NO metastasis (benign).
10. Macroscopic pictures of Multicystic, Solid
Ameloblastoma
• Starts in cancellous bone &
enlarge slowly.
• Extends buccal & lingual
plate of bone.
• There is always a continous
sheet of paper thin bone
covering the tumor.
• May be solid or cystic.
• Cystic tumor may be one
large (unicystic) or microcysts
(multicystic).
11. X-ray of Solid, Multicystic Ameloblastoma
• Multilocular
Radiolucency.
• (Honeycomb) or (soap-
bubble) appearance.
• Recently diagnosed by:
- Computed tomography
(CT) scan.
- Magnetic resonance
imaging (MRI).
12. C.T (3d) MRI for
scan for Ameloblastoma Ameloblastoma
13. Histological Features of Multicystic
Ameloblastoma
1-Follicular 2-Plexiform
Cystic
Acanthomatous
Granular
Basaloid
14. Histology of Follicular Ameloblastoma
• Epith.: Forms discrete islands.
Surrounded by CT stroma.
• Epith. Islands:
- Central cells →polyhedral or
angular cells similar to
(stellate reticulum).
- Surrounding layer →cuboidal
or columnar cells similar to
(internal enamel
epith.)(preameloblasts).
15. Histological Variants of Follicular
Ameloblastoma
• Cystic follicular:
- Due to cystic
breakdown of the
epith. Within the
follicle.
- The wall of the cyst
is formed of (flat
cells).
16. Histological Variants of Follicular
Ameloblastoma
• Acanthomatous follicular:
- Due to squamous
metaplasia of inner cells
within follicle.
- If ↑ keratin →(kerato
ameloblastoma).
- If some keratinised +
- another microcysts with
non-keratinised epith.+
- papillary forms→
(papilliferous kerato-
ameloblastoma).
17. Histological Variants of Follicular
Ameloblastoma
• Granular Follicular:
- Granular cell
metaplasia of inner
cells.
- Cuboidal rounded large
cells.
- Nuclei pushed to the
cell wall.
- Cytoplasm filled with
(eosinophilic granules).
19. Histology of Plexiform Ameloblastoma
• Epith.: arranged in
network.
• Lined by columnar or
cuboidal cells + cells similar
to (Stelate reticulum).
• Cystic formation → by
stromal breakdown NOT
epith.
• Stromal blood vessels
dialate → (Haemangio-
Ameloblastoma)
20. Connective Tissue (Stroma) Variants
• Acellular loose CT.
• OR, hyalaynization
around follicle (30µ
m).
• OR, more collagenous
stroma + small nests
& strands of epith.
→called
(Desmoplastic (Desmoplastic
Ameloplastoma) Ameloplastoma)
27. Histological Variants of Unicystic
Ameloblastoma
• Luminal type:
- The change is confined
within the luminal surface
of the cyst.
- Part of the epithelial lining
changes into ameloblastic
epithelium→ (columnar or
cuboidal c)+hyperchromatic
nuclei + reverse polarity.
- basilar cytoplasmic
vacoulation.
- The overlying epithelial
cells consist of loose
stellate reticulum like cells.
28. Histological Variants of Unicystic
Ameloblastoma
• Intraluminal type:
- The nodules of
ameloblastoma
proliferate and project
into the cyst lining.
- The lining often shows
an arrangement
similar to (plexiform
ameloblastoma).
29. Histological Variants of Unicystic
Ameloblastoma
• Mural type:
- The fibrous connective
tissue wall of the cyst is
infiltrated by
ameloblastic masses.
-The ameloblastic
component showing
(follicular or plexiform
patterns).
30. Adenomatoid Odontogenic Tumor (AOT)
• Def.:
- A tumor of odontogenic epith.with duct
structures & with varing degrees of inductive
changes in the C.T stroma.
- Its different clinically & histologically from
ameloblastoma.
- Its believed that the lesion is a (Hamartomatous)
in nature.
• Origin:
-Enamel organ & its remnants(Reduced E.E)
31. Clinical features of Adenomatoid
Odontogenic Tumor (AOT)
• Age: 2nd decade.
• Sex: F˂M.
• Site: Maxilla˂ Mand.
-↑↑impacted canine 50%.
• Signs & symptoms:
- Painless swelling.
-Slowly
growing(intraosseous)
- Associated with impacted
tooth.
- Similar to (Dentigerous
Cyst).
32. X-ray of (AOT)
• Unilocular.
• Well-defined.
• Radiolucencent.
• Associated with
impacted tooth.
• Especially upper
canine.
• Similar to
(Dentigerous cyst)
but its attachment
beyond the CEJ.
33. Histological Features of (AOT)
• The epith.:
- Whorled masses of spindle cells
or,Rings of columnar c.
• Rings of columnar c:
- Double layer tubular structure.
- Duct like structure.
- Convoluted bands.
- In between double layer +ve to
(PAS) stain.
• C.T stroma:hayline (epith.
Strands, dysplastic dentine&
rarly enamel matrix).
• Tumor is encapsulated
36. Calcifying Epith. Odontogenic Tumor (CEOT)
(Pindborg’s Tumor)
• Def.:
- It is a locally invasive epith. Neoplasm
characterized by the development of intra-
epith. Structure probably of an amyloid-like
nature.
- This amyloid-like structure may become
calcified & liberated into the surrounding
stroma.
• Origin (Histogenesis):
- (Reduced E.E) of associated unerupted tooth.
37. Clinical Features of (CEOT)(Pindborg’s
Tumor)
• Age: between 20-60 years.
• Sex: M=F
• Site:
- Intraosseous →mand˂max
(post.).
- Extraosseous→anterior.
• Signs & symptoms:
- painless.
- Slowly growing.
- Associated with impacted
tooth.
38. X-ray of (CEOT)(Pindborg’s Tumor)
• Irregular
radiolucent area.
• Containing
radioopaque
masses close to
unerupted tooth
44. Ameloblastic Fibroma
• Age: ˂ 21 years(young).
• Site: mand (post.).
• X-ray:
- impossible to
differentiated from
ameloblastoma.
- well-defined radiolucent.
- Associated with
impacted tooth
• Diagnosis: by histological
examination.
45. Histology of Ameloblastic Fibroma
1
•1→C.T: ↑↑cellular than ameloblastoma
( rounded or angular cells+ ↓↓ collagen)
•2→strands or islands of epith.
46. Histology of Ameloblastic Fibroma
2
1
•1→Peripheral epith.Columnar or cuboidal. Cells.
•2→narrow cell- free zone (halynization around
epith.).
•3→central stellate reticulum cells with NO cyst
formation.
47. Odontoma
Compound Odontoma Complex Odontoma
• Def.: a malformation in • Def.: a malformation in
which all dental tissues which all dental tissues
are represented in more are represented in more
orderly pattern than disorderly pattern.
comlex. • Contains many
• Contains many tooth- disordered tooth-like
like structures. structures.
• Don’t resemble the • Don’t resemble the
normal tooth normal tooth
morphologically . morphologically .
54. Histology of Odontogenic Fibroma
• Primitive cellular
fibroblastic tissue.
• Strands or islands of
inactive odontogenic
epith.
• Islands of ostoid or
cement-like tissue
scattered in the
fibroblastic mass.
• Invariable collagen.
• The tumor is
encapsulated.
56. Odontogenic Myxoma
• Def.:
It is a locally invasive neoplasm resembling dental
follicle in location & structure & containing:
- Angular spindle cells.
- Lying in mucoid stroma.
• Origin:
- Odontogenic mesenchyme because:
1- frequent inclusion of epith. Rests.
2- missing associated tooth.
3- no similar tumor in any bone type( only jaw).
4- similar histologically with embryonic mesenchyme.
57. Odontogenic Myxoma Clinically
• Age: young.
• Sex:F=M
• Site:
-only jaw bone ↑mand.
- In place of missing tooth.
• Signs & symptoms:
- Fusiform swelling.
- Rapidly growing.
- Difficult complete removal
(little encapsulation)
- may invade antrum.
