WHO Classification & Ameloblastoma

1. Dr. Ali Tahir

2. Index
4. Odontogenic tumours 77. Mesenchymal tumours
6. WHO classification 78. Odontogenic tumours
11. Ameloblastoma 85. Odontogenic myxoma
45. CEOT 90. Cementoblastoma
56. AOT 97. Mixed tumours
64. COC (Ghost cell
tumour)
72. Squamous odontogenic
tumour
Dr. Ali Tahir. M.Phil Oral Pathology

3. Tooth development
Dr. Ali Tahir. M.Phil Oral Pathology

4. Odontogenic Tumours
These tumors are unique to the jaws and originate from
remnants of epithelium, ectomesenchyme or mesenchyme
associated with tooth development, the abnormal tissue in
each of these tumors can often be correlated with similar
tissue in normal odontogenesis
Dr. Ali Tahir. M.Phil Oral Pathology

5. Classification
ODONTOGENIC
TUMORS
BENIGN MALIGNANT
Dr. Ali Tahir. M.Phil Oral Pathology

6. WHO CLASSIFICATION
BENIGN ODONTOGENIC TUMORS
According to the origin classified as:-
a. EPITHELIAL
b. MESENCHYMAL
c. MIXED
Dr. Ali Tahir. M.Phil Oral Pathology

7. BENIGN ODONTOGENIC TUMORS
ODONTOGENIC EPITHELIUM
1. AMELOBLASTOMA
2. SQUAMOUS ODONTOGENIC TUMOR
3. CALCIFYING EPITHELIAL ODONTOGENIC TUMOR
4. ADENOMATOID ODONTOGENIC TUMOR
5. KERATOCYSTIC ODONTOGENIC TUMOR
Dr. Ali Tahir. M.Phil Oral Pathology

8. BENIGN ODONTOGENIC TUMORS
ODONTOGENIC MESENCHYME (CONNECTIVE
TISSUE ONLY)
1. ODONTOGENIC FIBROM
2. ODONTOGENIC MYXOMA
3. BENIGN CEMENTOBLASTOMA.
Dr. Ali Tahir. M.Phil Oral Pathology

9. BENIGN ODONTOGENIC TUMORS
ODONTOGENIC EPITHELIUM WITH
ODONTOGENIC MESENCHYME (MIXED)
1. AMELOBLASTIC FIBROMA
2. AMELOBLASTIC FIBRODENTINOMA
3. AMELOBLASTIC FIBRO-ODONTOMA
4. ODONTOAMELOBLASTOMA
5. ODONTOMA
ODONTOMA COMPLEX TYPE
ODONTOMA COMPOUND TYPE
6. CALCIFYING CYSTIC ODONTOGENIC TUMOR
7. ODONTOGENIC GHOST CELL TUMOR
Dr. Ali Tahir. M.Phil Oral Pathology

10. MALIGNANT ODONTOGENIC TUMORS
ODONTOGENIC CARCINOMAS
1. MALIGNANT AMELOBLASTOMA
2. AMELOBLASTIC CARCINOMA
3. PRIMARY INTRAOSSEUS CARCINOMA
4. PRIMARY INTRAOSSEUS CARCINOMA
DERIVED FROM ODONTOGENIC
TUMOR/CYSTS
5. CLEAR CELL ODONTOGENIC CARCINOMA
6. GHOST CELL ODONTOGENIC CARCINOMA
Dr. Ali Tahir. M.Phil Oral Pathology

11. MALIGNANT ODONTOGENIC TUMORS
ODONTOGENIC SARCOMAS
1. AMELOBLASTIC FIBROSARCOMA
2. AMELOBLASTIC FIBRODENTINO AND
FIBRO- ODONTOSARCOMA.
Dr. Ali Tahir. M.Phil Oral Pathology

12. Dr. Ali Tahir. M.Phil Oral Pathology

13. Ameloblastoma
 Ameloblastoma is a locally aggressive, epithelial benign
odontogenic neoplasm having a close resemblance to the
enamel organ
 Most common odontogenic tumour in our region
Dr. Ali Tahir. M.Phil Oral Pathology

14. POSSIBLE EPITHELIAL SOURCES OF
AMELOBLASTOMA Cystic lining of odontogenic
cysts e.g.Dentigerous cyst
Surface Reduced
epithelium enamel
epithelium
remnants of dental
lamina
Rests of malassez
Dr. Ali Tahir. M.Phil Oral Pathology

15. TYPES OF AMELOBLASTOMA
It may present clinico-radiographically as:-
1. Central (Intraosseous)
I. Conventional, solid or multicystic (about 86% of all
cases).
II. Unicystic (about 13% of all cases)
2. Peripheral (extraosseuos) about 1% of all cases.
Dr. Ali Tahir. M.Phil Oral Pathology

16. Multicystic Unicystic
Peripheral
(extraosseous)
Dr. Ali Tahir. M.Phil Oral Pathology

17. COMMON OR MULTICYSTIC OR SOLID AMELOBLASTOMA
(INTRAOSSEOUS)
 This is also referred to as Simple or Follicular or True
ameloblastoma.
 Most common type.
 Occurs usually 20 to 40 years of age.
 Usually originate de novo, but may evolve from
unicystic or peripheral subtypes
Dr. Ali Tahir. M.Phil Oral Pathology

18. Clinical features
 May produce extensive,
even grotesque
deformities of jaws.
 More common in
mandible (80% of all
cases) than maxilla.
 Generally asymptomatic
 Can cause pain and
paresthesia when gets
infected.
Dr. Ali Tahir. M.Phil Oral Pathology

19. Dr. Ali Tahir. M.Phil Oral Pathology

20. Clinical features
 Eggshell cracking:-
It has tendency to
expand the boney
cortices as their slow
growth results in a thin
shell of bone and it
cracks easily when
palpated--- a diagnostic
sign.
Dr. Ali Tahir. M.Phil Oral Pathology

21. Radiographically
 These lesions usually
give MULTILOCLATION
(boney compartments)
appear as “SOAP
BUBBLE” or “HONEY
COMB”
 In rapidly growing
lesions roots may be
resorbed
Dr. Ali Tahir. M.Phil Oral Pathology

22. Ameloblastoma
Honey comb appearance
Dr. Ali Tahir. M.Phil Oral Pathology

23. HISTOPATHOLOGY
It has following histological variants
 Folicular ameloblastoma
 Plexiform ameloblastom
 Basal ameloblastom
 Granular cell ameloblastom
 Acanthomatous ameloblastom
 Desmoplastic ameloblastom
Common to all is the presence of neoplastic ameloblasts
with palisaded appearance and reverse polarisation
Dr. Ali Tahir. M.Phil Oral Pathology

24. Follicular variant
 Islands or follicles of epithelial cells composed
centrally of loosely arranged stellate cells with
columnar ameloblast-like cells at the periphery.
These islands resemble the enamel organ seen
during normal tooth development
 Cystic change may be seen within the follicles or in
the stroma
Dr. Ali Tahir. M.Phil Oral Pathology

25. Follicular variant
Dr. Ali Tahir. M.Phil Oral Pathology

26. Plexiform variant
 Long anastomosing cords
or large sheets of
odontogenic epithelium
which may lack reverse
polarization & may not
resemble any stage of
odontogenesis
 Also called “Fishnet
Pattern”
 Cystic change is
uncommon, if present it is
found in the stroma
Dr. Ali Tahir. M.Phil Oral Pathology

27. Acanthomatous variant
 When extensive
squamous metaplasia
often associated with
keratin formation
occurs in the central
portions of the epithelial
islands of a follicular
ameloblastoma
 May be confused with
SCC
Dr. Ali Tahir. M.Phil Oral Pathology

28. Desmoplastic ameloblastoma
 Small islands and cords of
odontogenic epithelium in
a densely collagenized
stroma
 More common in anterior
jaws
 Radiographically
resembles a fibro-osseous
lesion
 Clinically more aggressive
& more recurrence
Dr. Ali Tahir. M.Phil Oral Pathology

29. Granular Cell Variant
 Shows cells with
abundant cystoplasm
filled with eosinophilic
granules
 Clinically aggressive
Dr. Ali Tahir. M.Phil Oral Pathology

30. Basal Cell Variant
 Least common type
 Nests of basaloid cells &
histologically resembles
a BCC of skin
 No stellate reticulum can
be appreciated
Dr. Ali Tahir. M.Phil Oral Pathology

31. Treatment
 Treatments have ranged from
simple enucleation and
curettage to en bloc
resection.
 Marginal resection is the
most widely used method of
treatment with the least
recurrences reported (up to 15
%).
 Most surgeons advocate a
margin of at least 1.0 cm
beyond the radiographic
limits of the tumor as the
tumor often extends beyond
the apparent
radiologic/clinical margins
Dr. Ali Tahir. M.Phil Oral Pathology

32. UNICYSTIC AMELOBLASTOMA
 A biological subtype of ameloblastoma that is
predominantly cystic has been referred to as the unicystic
or cystic ameloblastoma
 Usually arises in a Dentigerous cyst
 Can be associated with impacted molar
 Usually occurs at 16 to 20 years
 More in mandible (90%)than maxilla
Dr. Ali Tahir. M.Phil Oral Pathology

33. Radiographically
 Well demarcated unilocular lesion
 May be corticated
 Impacted tooth may be present
 Roots may be displaced in premolar region.
Dr. Ali Tahir. M.Phil Oral Pathology

34. Histology
 Dense uniform fibrous connective tissue
 Fluid filled lumen
 Lining made up of hyperchromatic, palisaded basal
cells showing reverse polarization
 Rest of the layers resemble stellate reticulum
Dr. Ali Tahir. M.Phil Oral Pathology

35. Types of Unicystic Ameloblastoma
 Intra-luminal U.A.
 Mural U.A.
 Plexiform U
Dr. Ali Tahir. M.Phil Oral Pathology

36. Dr. Ali Tahir. M.Phil Oral Pathology

37. Peripheral Ameloblastoma
 These tumors are extraosseous and therefore occupy
the lamina propria underneath the surface epithelium
but outside of the bone
 Histologically, these lesions have the same features as
the intraosseous forms of the tumor.
Dr. Ali Tahir. M.Phil Oral Pathology

38. Clinical Features
 Patient Age: Wide age
range but most occur
during middle-age
 Location: Posterior
gingival/alveolar mucosa is
involved most frequently.
 Firm, sessile nodule
 Normal coloration, if arises
from surface epith, may be
ulcerated
 Slight predilection for the
mandible. The buccal
mucosa has been the site
in a few reported cases.
Dr. Ali Tahir. M.Phil Oral Pathology

39. Peripheral Ameloblastoma
 Radiographically:
 A few cases have shown superficial erosion of alveolar
bone
 Histologic Appearance:
 Islands of ameloblastic epithelium are observed in the
lamina propria; follicular patterns are the most
common; acanthomatous pattern may be seen
 In 50 % of the cases the tumor connects with the basal
cell layer of the surface epithelium
Dr. Ali Tahir. M.Phil Oral Pathology