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
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
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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
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
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
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
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30. Basal Cell Variant
Least common type
Nests of basaloid cells &
histologically resembles
a BCC of skin
No stellate reticulum can
be appreciated
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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.
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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
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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