This document defines and describes odontogenic tumors, which are neoplasms or tumor-like malformations arising from odontogenic tissues. It classifies various odontogenic tumors based on their origin from odontogenic epithelium, mesenchyme, or mixed tissues. Key tumors discussed include ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), and ameloblastic fibroma. Clinical features, imaging findings, and histopathological characteristics are provided for each tumor type.

1. Odontogenic Tumors

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)

4. (Odontogenic Tissues)

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).

18. Histological Variants of Follicular
Ameloblastoma
• Basaloid
(basal cell follicular):
- Inner cells →compact.
- Peripheral→ cuboidal.

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)

21. Epith.
Epith.
C.T
C.T
Plixiform Multicystic Follicular Multicystic
Ameloblastoma Ameloblastoma

23. Unicystic Ameloblastoma
• Def.: Locally invasive
tumor consists of a central
large cystic cavity.
• Age: ˂20 years.
• Sex: male= female.
• Site: mand.˂ maxilla.
• Signs & symptoms:
- ↓ aggressive.
- ↓ recurrence rate.
- Painless &Slowly growing.
• X-ray:
Unilocular radiolucent.

24. (3D) CT scan of Unictystic
Ameloblastoma

25. Histology of Unicystic Ameloplastoma
One large
expansile cyst

26. Histological Variants of Unicystic
Ameloblastoma
1- Luminal
2-
Intraluminal 3-Mural

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

34. Rings
Duct like
structure
Whorled
masses

35. AOT is encapsulated with thick
fibrous band

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

39. (3D) CT scan of Pindborg’s
Tumor (CEOT)

40. Histology of (CEOT)(Pindborg’s Tumor)
• The epith.:
• Sheets of polyhedral cells.
• Well-defined cell border.
• Giant nuclei, prominent
nucleoli & darkly stained.
• No mitosis ( benign).
• Clear cell variant.
• (Liesegang’s ring):
- Rounded acidophilic
homogenous amyloid
masses→calcify→ring –
shaped,+ve Thiovlavin T stain.

41. -Red rose→amyloid spaces.
-Black arrows→Liesegang’s ring
-E→ epith. Polyhedral cells

42. Sheet of
polyhedral
epith.

43. Mixed Odontogenic Tumors
(Epith.+ Mesenchyme)
•Ameloblastic fibroma.
•Odontoma (complex & compound)

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 .

48. X-ray of Odontoma
Compound Complex
Odontoma Odontoma

49. Macroscopic Pictures of Odontoma
(compound &complex)

50. Microscopic Pictures of Odontoma
(compound &complex)
Compound Complex
Odontoma Odontoma

51. Mesenchymal Odontogenic Tumors
from (Mesenchymal Tissues)
•Odontogenic Fibroma.
•Odontogenic Myxoma.

52. Odontogenic Fibroma
• Def.:
A fibroblastic neoplasm containing:
- Inactive odontogenic epith.
- More cellular fibrous tissue.
- Hard tissue (dysplastic cementum or bone).
• Origin:
-Tooth follicle (dental sac) →fibroblastic
elements or,
- Its derivative ( periodontal ligament)

53. X-ray of Odontogenic Fibroma
Well-defined (unilocular)
monolocular radioucency

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.

55. 3
1
2
•1→fibroblastic tissue
•2→ostoid islands
•3→ inactive epith. strands

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.

58. Odontogenic Myxoma Radiographically
•Multilocular radiolucencies
•Soap-bubbles appearance.

59. Odontogenic Myxoma Histologically
1
3
2
•1→myxoma filling marrow spaces.
•2→bony trabaculea.
•3→spindle cells in mucoid matrix.

60. Thanks
Presented by:
Marwa Assem Salama