Odontogenic tumors arise from tooth-forming tissues and can be divided into three categories: tumors of odontogenic epithelium without mesenchyme, tumors with both epithelium and mesenchyme, and tumors of mesenchyme alone. Ameloblastoma is the most common odontogenic tumor, representing 1% of jaw tumors. It typically presents as a multilocular radiolucency in the mandible and is classified as solid/multicystic, unicystic, or peripheral. Histologically it demonstrates islands of epithelial cells resembling dental lamina. Treatment involves wide local excision due to its persistence and recurrence.

1. ODONTOGENIC TUMOURS
Dr Archana Mukunda
1

2. INTRODUCTION
 Group of lesions arising from the tooth- producing
apparatus or its remnants
 May originate from epithelial and/or
ectomesenchymal odontogenic tissues
 1% of all jaw tumors
2

3. WHO HISTOLOGICAL TYPING OF ODONTOGENIC
TUMORS
1992 (MODIFIED)
 Tumors of odontogenic epithelium without
odontogenic ecto-mesenchyme
 Tumors of odontogenic epithelium with odontogenic
ecto-mesenchyme with or without dental hard tissue
formation (mixed)
 Tumors of odontogenic ecto-mesenchyme with or
without odontogenic epithelium
3

4. TUMORS OF ODONTOGENIC EPITHELIUM WITHOUT
ODONTOGENIC ECTO-MESENCHYME
 Ameloblastoma
 Calcifying epithelial odontogenic
tumor (CEOT)
 Clear cell odontogenic tumor
 Squamous odontogenic tumor
4

5. TUMORS OF ODONTOGENIC EPITHELIUM WITH
ODONTOGENIC ECTO-MESENCHYME WITH OR
WITHOUT DENTAL HARD TISSUE FORMATION (MIXED)
• Ameloblastic fibro odontoma
• Adenomatoid odontogenic tumor (AOT)
• Ameloblastic fibroma
• Odontomes
 Compound
 Complex
5

6. TUMORS OF ODONTOGENIC ECTO-MESENCHYME WITH
OR WITHOUT ODONTOGENIC EPITHELIUM
 Odontogenic fibroma
 Odontogenic myxoma
 Cementoblastoma
6

7. MALIGNANT ODONTOGENIC TUMORS
 Odontogenic carcinoma
a. Malignant ameloblastoma
b. Primary intraosseous carcinoma
c. Malignant variant of other odontogenic epithelial tumors
d. Malignant changes in odontogenic cyst
 Odontogenic sarcoma
a. Ameloblastic fibrosarcoma
b. Ameloblastic fibrodentinosarcoma
7

8. 8

9. TUMORS OF ODONTOGENIC EPITHELIUM MATURE FIBROUS
STROMA WITHOUT ODONTOGENIC ECTO-MESENCHYME
 Ameloblastoma: Solid/ multicystic
 Ameloblastoma: Extraosseous/Peirpheral
 Ameloblastoma: desmoplastic type
 Ameloblastoma: Unicystic type
 Squamous odontogenic tumor
 Calcifying epithelial odontogenic tumor (CEOT)
 Adenomatoid odontogenic tumor
 Keratocystic odontogenic tumor
9

10. TUMORS OF ODONTOGENIC EPITHELIUM WITH ODONTOGENIC
ECTO-MESENCHYME WITH OR WITHOUT DENTAL HARD TISSUE
FORMATION
• Ameloblastic fibroma
• Ameloblastic fibrodentinoma (dentinoma)
• Ameloblastic fibro odontoma
• Odontomes
 Compound type
 Complex type
 Odontoameloblastoma
 Calcifying cystic odontogenic cyst
 Dentinogenic ghost cell tumor
10

11. TUMORS OF MESENCHYME AND/ OR ODONTOGENIC ECTO-
MESENCHYME WITH OR WITHOUT ODONTOGENIC EPITHELIUM
 Odontogenic fibroma
 Odontogenic myxoma/ Myxofibroma
 Cementoblastoma
11

12. BONE RELATED LESIONS
Other tumors – Melanotic neuroectodermal tumor of infancy
12
• Ossifying fibroma (Cemento Ossifying fibroma)
• Fibrous dysplasia
• Osseous dysplasia
• Cemento osseous dysplasia
Periapical cemental dysplasia
Focal cemento osseous dysplasia
Florid cemento osseous dysplasia
• Central Giant cell granuloma
• Cherubism
• Aneurysmal bone cyst
• Simple bone cyst

13. MALIGNANT TUMORS OF ODONTOGENIC ORIGIN
 Odontogenic carcinoma
a. Malignant ameloblastoma
b. Ameloblastic carcinoma: Primary type (intraosseous)
c. Ameloblastic carcinoma: Secondary type (peripheral)
d. Primary intraosseous squmaous cell carcinoma
e. Primary intraosseous squmaous cell carcinoma derived
Keratocytsic odontogenic tumor
f. Primary intraosseous squmaous cell carcinoma derived from an
odontogenic cyst
g. Clear cell odontogenic carcinoma
h. Ghost cell odontogenic carcinoma
Odontogenic sarcomas
a. Ameloblastic fibrosarcoma (ameloblastic sarcoma)
b. Ameloblastic fibrodentinoma sarcoma & fibro odontosarcoma
13

14. 14
2017 WHO classification of
odontogenic tumors and cysts
Malignant odontogenic
tumors
Benign odontogenic
tumors
• Epithelial origin
• Mixed (Epi-mes)
origin
• Mesenchymal origin

15. 15
Benign odontogenic tumors
Epithelial origin
Ameloblastoma
Conventional
Unicystic
Extra-osseous/ Peripheral
Metastasizing (Malignant) ameloblastoma
Squamous odontogenic tumor
Calcifying epithelial odontogenic tumor
Adenomatoid odontogenic tumor

16. 16
Mixed (Epi- Mesenchymal)
origin
Ameloblastic fibroma
Primary odontogenic tumor
Odontoma
Compound
Complex
Dentinogenic ghost cell
tumor
Mesenchymal origin
Odontogenic fibroma
Odontogenic myxoma/
myxofibroma
Cementoblastoma
Cemento-ossifying
fibroma

17. 17
2017 WHO classification of
odontogenic tumors and cysts
Malignant odontogenic tumors
• Ameloblastic carcinoma
• Primary intraosseous carcinoma, NOS
• Scleorsing Odontogenic carcinoma
• Clear cell odontogenic carcinoma
• Ghost cell odontogenic carcinoma
• Odontogenic carcinosarcoma
• Odontogenic sarcomas

18. 18
Odontogenic
cysts
Developmental origin
Dentigerous cyst
Odontogenic keratocyst
Lateral Periodontal cyst & botryoid
odontogenic cyst
Gingival cyst
Glandular odontogenic cyst
Orthokeratinized OKC
Inflammatory origin
Radicular cyst
Collateral inflammatory cyst

19. AMELOBLASTOMA
19

20.  Common odontogenic tumour
 1% of all oral tumours
20
Introduction

21. CONTENTS
 Definition
 Histogenesis
 Clinico-radiologic
classification
 Radiographic features
 Histologic features
 Differential
diagnosis
 Diagnosis
 Treatment &
Prognosis
 Miscellaneous
21

22. DEFINITION
Ameloblastoma is a tumor that is “usually
unicentric, non-functional, intermittent
in growth, anatomically benign and
clinically persistent”.
-Robinson
22

23. HISTOGENESIS
 Cell rests of the enamel organ
(remnants of dental lamina or HERS)
 Epithelium of odontogenic cysts (esp. D C)
 Disturbance of the developing enamel organ
 Basal cells of oral mucosal epithelium
 Heterotopic epithelium
23

24. CLINICO-RADIOLOGIC CLASSIFICATION
24
Conventional / solid /
multi-cystic / intra-
osseous
86%
Unicystic 13%
Peripheral / extra-osseous 01%

25. INTRA-OSSEOUS / SOLID /
MULTI-CYSTIC AMELOBLASTOMA
25

26. CLINICAL FEATURES
 20 – 40 years, M=F, blacks?
 Mandible > maxilla, posterior > anterior
 Asymptomatic, painless swelling / expansion
of the jaw, slowly destructive, no ulceration of
mucosa
 Resorption of roots of teeth
 Palpation ‘egg shell crackling’
26

27. 27

28. 28
Radiographic
Features
 Multilocular,cyst-like
radiolucent areas with
well-defined margins
‘Honey-comb’pattern
‘Soap-bubble’ appearance
 Bony margins 
typically scalloped

29. 29
• Roots of adjacent teeth
may be resorbed or
displaced
• Expansion of buccal
and lingual cortical
plates

30. 30

31. 31

32. HISTOPATHOLOGICAL FEATURES
Six histopathological subtypes
 Follicular
 Plexiform
 Acanthomatous
 Basal cell
 Granular cell
 Desmoplastic
32

33.  Mixture of different patterns is
common
 A lesion may exhibit one or more
histologic patterns
 Lesions are sub-classified according
to the most predominant pattern
33

34. FOLLICULAR AMELOBLASTOMA
 Islands of epithelial cells in a connective
tissue stroma
 Epithelial islands have a core of loosely
arranged polygonal cells (resembling stellate
reticulum), surrounded by a peripheral layer
of tall, columnar ameloblast-like cells with
polarized nuclei
 Cyst formation: microcysts to generally cystic
tumour (degeneration of stellate reticulum-like
cells).
34

35. 35

36. 36

37. 37

38. 38
Enlarged islands with cystic degeneration

39. 39

40. ACANTHOMATOUS AMELOBLASTOMA
 Squamous metaplasia of central core
of stellate reticulum-like cells with
keratin formation
 Otherwise resembles follicular variety
40

41. 41

42. 42

43. 43

44. 44

45. GRANULAR CELL AMELOBLASTOMA
 Relatively rare subtype
 Resembles follicular type, but center of the
tumour islands form sheets of large
eosinophilic granular cells
 Cytoplasmic granules consist of pleomorphic,
lysosome-like organelles
 Aggressive variant with highest recurrence
rate
45

46. 46

47. 47

48. DESMOPLASTIC AMELOBLASTOMA
 Scattered tumor islands in dense
fibrous stroma
48

49. 49

50. 50

51. 51

52. BASAL CELL AMELOBLASTOMA
 Least common type
 Occurs primarily in extra-osseous lesions
 Nests of basaloid cells occupy the central
portions of the islands (no stellate reticulum-like
tissue)
52

53. 53

54. 54

55. CLEAR CELL AMELOBLASTOMA
55

56. PLEXIFORM AMELOBLASTOMA
 Network of thin (inter-connecting)
strands of epithelium bordered by
columnar cells
 Loose, vascular, sparsely cellular or
fibrous stroma may show areas of
cystic degeneration
56

57. 57
Plexiform ameloblastoma

58. 58
Plexiform ameloblastoma

59. DIFFERENTIAL DIAGNOSIS
 CEOT (radiolucent type)
 Odontogenic myxoma
 Cysts (dentigerous,radicular, keratocyst)
 Central giant cell granuloma
 Ossifying fibroma
 Central haemangioma
 Squamous cell carcinoma
59

60. TREATMENT AND PROGNOSIS
 Aggressive lesion; extensive treatment
 Wide excision; resection of jaw
 Recurrence common
60

61. CLINICO-RADIOLOGIC CLASSIFICATION
 Conventional / solid / multi-cystic / intra-
osseous: 86%
 Unicystic: 13%
 Peripheral / extra-osseous: 1%
61

62. UNICYSTIC AMELOBLASTOMA
 10 – 15% of all ameloblastomas
 Younger patients (< 30 years)
 Males > females
 Posterior mandible
 Mostly asymptomatic;painless swelling
of jaws
62

63. PATHOGENESIS
 Arise de novo
 From neoplastic transformation of cyst
epithelium
63

64. CLINICAL FEATURES
 Younger age group (22.1years)
 Mandible (90%)- Posterior region
 Higher percentage associated with
impacted teeth
64

65. RADIOGRAPHIC FEATURES
 Unilocular, well-defined radiolucency,
frequently containing a tooth
(mostly un-erupted third molar)
65

66. HISTOLOGIC FEATURES
 Single cystic cavity that shows
ameloblastomatous differentiation in the
lining
Types:
 Luminal ameloblastoma
 Intraluminal / Plexiform unicystic ameloblastoma
 Mural ameloblastoma
66

67. SHEAR
67
3A 3B
1 2

68. 68
Vickers and Gorlin criteria
(for diagnosis of ameloblastoma)
 Columnar basal cells
 Reversal of nuclear polarity
 Nuclear palisading
 Hyperchromatic nuclei
 Cytoplasmic vacuolation

69. Luminal ameloblastoma
69

70.  Intraluminal / Plexiform unicystic
ameloblastoma:
 Intraluminal plexiform proliferation, but no
infiltration of the cyst wall
(i.e., projects only into the lumen).
70

71. INTRALUMINAL UNICYSTIC AMELOBLASTOMA
71

72.  Mural ameloblastoma
 Invasive islands of follicular or plexiform type of
ameloblastoma, sometimes continuous with cyst
lining, infiltrate the cyst wall.
72

73. MURAL UNICYSTIC AMELOBLASTOMA
73

74. 74
Mural unicystic ameloblastoma

75. DIFFERENTIAL DIAGNOSIS
 Radicular cyst
 Residual cyst
 Dentigerous Cyst
 Odontogenic Keratocyst
75

76. TREATMENT AND PROGNOSIS
 Enucleation and curettage
 Low recurrence rate: 10-15%
 Long term follow-up and radiographs
76

77. PERIPHERAL (EXTRA-OSSEOUS)
AMELOBLASTOMA
 Uncommon (1% of all ameloblastomas)
Histogenesis
 Originates either from remnants of
dental lamina or surface epithelium
77

78. CLINICAL FEATURES
 Painless non-ulcerated, sessile /
pedunculated lesion on gingiva or alveolar
mucosa; < 2 cm size
 Middle age; mandible > maxilla
 Slow-growing; superficial erosion of bone
78

79. 79

80. RADIOGRAPHIC FEATURES
 Rarely produces saucerization of underlying
bone
HISTOLOGIC FEATURES
 Mostly acanthomatous > plexiform >
follicular type
80

81. 81
Peripheral ameloblastoma

82. DIFFERENTIAL DIAGNOSIS
 Peripheral odontogenic fibroma
(lacks polarized cells, contains dysplastic dentin or
cementum).
82

83. TREATMENT AND PROGNOSIS
 Relatively innocuous clinical behaviour.
 Low recurrence rate (25%).
83

84.  Craniopharyngioma/Pituitary ameloblastoma
(copious ghost cell production, cystic morphology, and
the presence of osteoid or bone).
 Adamantinoma of long bones
(lack the regular shape and reversed nuclear polarity of
ameloblastoma cells).
84
Extra-oral tumours resembling
Ameloblastoma

85. MALIGNANT AMELOBLASTOMA
An ameloblastoma that has given rise
to pulmonary or nodal metastases and
the metastases have retained the
microscopic appearances of the
primary growth
85

86. AMELOBLASTIC CARCINOMA
Ameloblastoma that has cytologic features
of malignancy in the primary lesion or in a
metastasis. Later, the metastases tend to
resemble less well-differentiated squamous
cell carcinoma
86

87. PRIMARY INTRA-OSSEOUS CARCINOMA
 Resemble SCC with cells exhibiting
pleomorphism, hyperchromatism, varied
mitotic activity
 D/D: Acanthomatous ameloblastoma
87

88. CEOT
 Calcifying Epithelial Odontogenic
Tumour
 Also known as “Pindborg tumor”
88

89. HISTOGENESIS
 From stratum intermedium (cell resemble &
high alk phosphatase activity)
 Reduced enamel epithelium?
89

90. CLINICAL FEATURES
 Occurs over a wide range from 3-92
years; (average = 40 years)
 Mandible > maxilla; molar region
 Painless, slow-growing swelling
 May be associated with unerupted or
impacted tooth (third molars)
90

91.  Extra-osseous (peripheral) CEOT
 Non-specific
 Sessile, gingival masses commonly on anterior
gingiva
91

92. RADIOGRAPHIC FEATURES
May exhibit considerable variation
• Diffuse or well-circumscribed radiolucent area
(may be with an impacted tooth)
• Mixed radiolucent / radio-opaque picture with
many small irregular bony trabeculae traversing
the radiolucent area
• Multilocular or ‘honeycomb’ pattern
• Scattered flecks of calcification in the RL areas-
‘driven –snow’ appearance
• Peripheral CEOT- saucerization of underlying
92

93. 93

94. HISTOLOGIC FEATURES
 Islands, sheets or strands of pleomorphic, slightly
eosinophilic epithelial cells in a connective tissue
stroma
 Distinct cell membranes and intercellular bridges
of epithelial cells
 Nuclei vary in number, size and shape
 Mitosis is rare
 Presence of a homogeneous eosinophilic
amyloid-like substance, which may calcify to form
concentrically lamellated ‘Liesegang rings’
94

95. 95

96. TUMOR CELLS WITH LARGE CENTRALLY LOCATED
HYPERCHROMATIC NUCLEI
96

97. TUMOR CELLS WITH VARIABILITY IN NUCLEAR SIZE, SHAPE AND
STAINING
97

98. 98
Amyloid- homogenous eosinophilic substance
Thought to be
• Filamentous degeneration of keratin
filaments conversion into amyloid
• Tissue degeneration
• Type IV collagen
• Basal lamina
• Enamel matrix

99. FIBROUS CONNECTIVE TISSUE STROMA CONTAINING
HYALINIZED DEPOSITS OF CONGO RED-POSITIVE AMYLOID
99

100. APPLE GREEN BIREFRINGENCE UNDER POLARIZED LIGHT
100

101. CALCIFICATION OF AMYLOID-LIKE DEPOSITS
101
• Presence or absence of calcification in
CEOT has prognostic implications
• Lack of calcification indicates less tumor
differentiation and hence favors more
chance of recurrence

102. CONCENTRIC LAYERS OF CALCIFICATION WITHIN AMYLOID-LIKE
MATERIAL  LIESEGANG RINGS
102

103. Amyloid-like material is PAS-negative
Liesegang rings are PAS-positive
103

104. CLEAR CELL VARIANT OF CEOT
 Cells have clear vacuolated cytoplasm with
round or oval nuclei, or nuclei flattened
against the cell membrane
 Clear cells comprise the bulk of the tumour,
or are seen in a few scattered foci
 Clear cells are mucicarmine-negative
104

105. CLEAR CELL CHANGE
105

106. DIFFERENTIAL DIAGNOSIS
Radiolucent lesions:
• dentigerous cyst
• OKC
• ameloblastoma
• odontogenic myxoma
106
Mixed RL-RO lesions:
• COC
• AOT
• Ossifying fibroma
• osteoblastoma
• ameloblastic fibro-
odontoma

107. TREATMENT AND PROGNOSIS
 Excision to resection
 Low rate of recurrence
 Slow growth and locally invasive
 Does not metastasize
107

108. ADENOMATOID
ODONTOGENIC TUMOUR
(AOT)
108

109. ADENOMATOID ODONTOGENIC
TUMOUR
(AOT)
 (Adenoameloblastoma,
Ameloblastic adenomatoid tumour)
 Characterised by formation of duct-like structures by
epithelial component of the lesion
 Uncommon; completely benign; may be hamartomas
 1992 WHO classification it was under epi-mes tumor
 2005 WHO classification & 2017 its under epithelial
without ectomesenchyme origin
109

110. INCIDENCE
 10- 20 years
 ♀ : ♂ : 2:1
 Maxilla > mandible (anterior maxilla); cuspid,
unerupted tooth
110

111. CLINICAL FEATURES
 Slow growing, painless swelling;
< 3cm in size
 May be associated with an
unerupted tooth (cuspid)
111

112. 112
2/3rd of cases occur in 2nd decade
2/3rd of cases occur in females
2/3rd of cases occur in ant maxilla
2/3rd of cases associated with
unerupted canine
2/3rd tumor

113. RADIOGRAPHIC FEATURES
 Rounded radiolucency with well-
defined outline with faint radio-opaque
foci
 (‘snow-flake’ calcifications) in 60% of
cases.
 Displacement of adjacent teeth / roots;
resorption is rare
113

114. 114
2 variants :
1. Follicular variant – tumour contains a tooth
2. Extra follicular variant – no tooth in the
tumour; seen between roots of teeth

115. HISTOGENESIS
 Remnants of the dental lamina
115

116. HISTOLOGIC FEATURES
 Well-defined capsule
 Spindle-shaped or cuboidal epithelial
cells in sheets, whorls, strands; may
form rosettes
 Columnar or cuboidal cells arranged in
ductal pattern, with ductal lumina
containing eosinophilic coagulum
116

117. HISTOLOGIC FEATURES
 Loose, scanty, sparsely cellular connective
tissue stroma
 Fragments of amorphous or crystalline
calcification (possibly amyloid) seen among
sheets of epithelial cells
 Small foci of calcification scattered throughout
the tumour (attempted formation of enamel or
dentine or cementum)
117

118. 118

119. 119

120. MICROCYSTS LINED BY CUBOIDAL TO COLUMNAR CELLS WITH PALE BASOPHILIC
FLOCCULENT MATERIAL AND RESIDUAL DROPLETS OF EOSINOPHILIC MATERIAL
120

121. COLUMNAR CELLS IN THE
FORM OF ROSETTES
121

122. 122

123. 123
AOT

124. DIFFERENTIAL DIAGNOSIS
 Dentigerous cyst
 Lateral periodontal cyst
 CEOT
 COC
124

125. TREATMENT
 Conservative treatment; enucleation
 Recurrence very rare
125

126. ODONTOMAS
126

127.  Hamartomas
 Most common odontogenic tumour
127

128.  Complete differentiation of epithelial
and mesenchymal cells
￫ functional ameloblasts and odontoblasts
￫ enamel and dentin formation
 Improper morpho-differentiation of
odontogenic cells
￫ haphazard deposition of enamel and dentin
128

129.  Three types (WHO classification)
 Complex odontoma
 Compound odontoma
 Odontoameloblastoma
129

130.  Compound composite odontoma :
 regular arrangement
 resemble normal teeth / denticles
(smaller size)
 Complex composite odontoma:
 irregular mass of dental tissue
 no morphological resemblance to a tooth
130

131.  Odontoameloblastoma:
 Extremely rare odontogenic tumour
 Consists of simultaneous occurrence of
ameloblastoma and composite odontome
131

132. ETIOLOGY
 Unknown
 Trauma
 Infection
 Inherited
 Mutation
132

133. CLINICAL FEATURES
 Any age
 any site
 maxilla : mandible: : 2:1
 right side > left
 compound > complex
 compound – anterior maxilla
 complex – posterior jaws
133

134.  Small
 Asymptomatic, but may result in unerupted /
impacted teeth, retained deciduous teeth
134

135. RADIOGRAPHIC FEATURES
 Irregular mass of calcified material / variable
number of tooth like structures surrounded by
a narrow radiolucent band with a smooth
periphery
 Between the roots of teeth
 Associated with unerupted /impacted tooth
135

136. COMPOUND ODONTOME
136

137. COMPLEX ODONTOME
137

138. HISTOPATHOLOGICAL FEATURES
 Normal appearing dental tissues
(that may or may not resemble
normal teeth) in a fibrous connective
tissue
 Presence of ‘ghost’ cells
138

139. COMPOUND ODONTOME
139

140. COMPOUND ODONTOMA
140

141. COMPOUND ODONTOMA
141

142. 142
Complex odontome

143. COMPLEX ODONTOMA CONSISTING OF
SHEETS OF TUBULAR DENTIN AND ENAMEL
SPACES
143

144. COMPLEX ODONTOMA
144

145. ODONTOMA SHOWING TUBULAR DENTIN AND
ENAMEL MATRIX WITH PRISMATIC STRUCTURE
145

146. COMPLEX ODONTOMA WITH GHOST CELLS
146

147. DIFFERENTIAL DIAGNOSIS
 Focal sclerosing osteomyelitis
 Osteoma
 Periapical Cemental Dysplasia
 Ossifying fibroma
 Cementoblastoma
147

148. TREATMENT
 Enucleation
 Good prognosis
 Limited growth potential
148

149. AMELOBLASTIC
FIBROMA
149

150. Neoplasms composed of proliferating
odontogenic epithelium embedded in a
cellular ectomesenchymal tissue that
resembles the dental papilla, with varying
degrees of inductive change and dental
hard tissue formation.
(WHO definition, 1992)
150

151.  Simultaneous proliferation of both
epithelial and mesenchymal tissue
without formation of enamel or
dentin
151

152. CLINICAL FEATURES
 posterior region of mandible
 14.6 yrs
 ♂
 mostly asymptomatic; sometimes
associated with pain, tenderness or
mild swelling
152

153. RADIOGRAPHIC
FEATURES
 Unilocular or multilocular
radiolucency with smooth outline
and sclerotic border, with / without
bulging of bone
153

154. HISTOLOGICAL FEATURES
 Epithelial component
 Mesenchymal component
 Dense fibrous capsule
154

155. ISLANDS OF ODONTOGENIC EPITHELIUM WITH
PERIPHERAL AMELOBLAST-LIKE CELLS AND
ECTOMESENCHYMAL STROMA RESEMBLING
DENTAL PAPILLA
155

156.  Epithelial component:
 cuboidal or columnar cells in sheets, strands,
nests, cords, rosettes
 rare mitosis.
156

157. HIGH POWER VIEW SHOWING CENTRAL
STELLATE RETICULUM-LIKE CELLS
157

158. SLENDER STRANDS OF ODONTOGENIC
EPITHELIUM LACKING STELLATE
RETICULUM-LIKE CELLS
158

159. DOUBLE LAYER OF COLUMNAR CELLS AND MORE
CELLULAR STROMA (HIGH POWER VIEW)
159

160.  Mesenchymal component:
 primitive connective tissue
 decrease in blood vessels
 juxta-epithelial hyalinisation of areas of
connective tissue
(resemble dysplastic dentin or exuberant basal
lamina)
160

161. TREATMENT
 Aggressive surgical removal (because of
recurrences that turn malignant)
161

162. AMELOBLASTIC
FIBRO ODONTOMA
162

163. A lesion similar to ameloblastic fibroma,
but showing inductive changes that lead
to formation of dentin and enamel.
(WHO Definition)
163

164.  Hamartoma
Ameloblastic fibroma
+
Complex odontoma
164

165. CLINICAL FEATURES
 < 10 yrs
 asymptomatic
 failure of tooth to erupt
 swelling
165

166. RADIOGRAPHIC FEATURES
 Well-circumscribed solitary / multiple
small radio-opacities
166

167. HISTOLOGICAL FEATURES
 Combination of ameloblastic fibroma and
odontoma.
167

168. TYPICAL AMELOBLASTIC FIBROMA-LIKE
AREA MERGING WITH ODONTOMA-LIKE
AREA
168

169. INDUCTION OF THIN LAYER OF
ATUBULAR DENTIN IN THE STROMA BY
THE AMELOBLAST-LIKE CELLS
169

170. PRIMORDIAL ODONTOGENIC TUMOR
 1st described by Mosqueda-Taylor et al
 Benign odontogenic tumor developing during
primordial stages of tooth developemnt
 Classified under mixed odontogenic tumors- dental
papilla surrounded by delicate ameloblastic
epithelium
 Only around 14 cases reported until now
 Occurs in young age- 2nd decade of life
170

171. PRIMORDIAL ODONTOGENIC TUMOR
 Slight male predilection
 Mandible the most common site; unerupted tooth
 Asymptomatic swelling presenting with expansion
of cortical bone
171

172. X- ray:
 large well defined radiolucency
 involving an completely unerupted tooth – 3rd
molar
 Root resorption seen
 Buccal and lingual cortical plate expansion
 Gross findings
 Encapsulated solid nodule, pale, slippery
172

173. 173

174. 174
DD
Ameloblastic fibroma
Central odonotgenic fibroma
Odontogenic myxoma

175. Histopathology
 Variably cellular to loose fibrous tissue with
areas mimicking dental papilla surrounded
by epithelial cells – cuboidal to columnar
 No hard tissue formation
 Calcifications may be seen in myxoid CT
stroma
175

176. 176

177. Treatment
 Enucleation and extraction of involved tooth
 Conservative surgical excision
 Prognois – good
 Recurrences- rare
177

178. DENTINOGENIC GHOST
CELL TUMOR
 COC was first described by Gorlin and his colleagues in 1962,
 Controversy as to whether COC is a cyst or a tumor
 Two organizing principles of classification of
 Monistic concept: postulates that all COCs are neoplastic in
nature, even though the majority are cystic in architecture and
appear to be non-neoplastic
 Dualistic concept favored by most researchers proposes that
COCs contain two different entities- cyst & Tumor
Cyst- “Calcifying Cystic Odontogenic Tumors” (CCOT)
Neoplasm-“Dentinogenic Ghost Cell Tumor” (DGCT)
178

179.  DGCT term 1st proposed by Praetorius et al. in 1981 for
the neoplastic variety of COC, i.e., the Type 2 of COC
 DGCT has also been termed as odontogenic ghost cell
tumor by Colmenero et al.
 DGCT is an extremely rare odontogenic tumor
 Central and a peripheral type
179
Histogenesis- cell rests of Serre or the surface epithelium but
unclear
β-catenin plays an important role in the tumorigenesis of DGCT
by an improper differentiation process coordinated by Wnt
signaling pathway

180.  Age- 50yrs (17-72yrs)
 Slight male predilection
 Maxilla = Mandible
 Canine to 1st molar region affected
 Asymptomatic – few pain & discomfort
 Tooth bearing area or edentulous jaw
180

181. X rays shows
 Unilocular & multilocular
 Radiolucency with scattered radio-opaque calcifications
 Occlusal radiographs show a bicortical expansion
 Root resorption or an impacted tooth in relation to the tumor
mass is also noted in some cases
181

182. 182

183. Histopathology
 Islands of odontogenic epithelium
 Tall columnar ameloblast-like cells with hyperchromatic nuclei
 Large areas of eosinophilic globules suggestive of dentinoid
 Ghost cells showing keratinization and calcification
183
Dentin like
Calcification in
ghost cells
Giant cell

184. Treatment
 Enucleation or surgical resection- enbloc, segmental
 Locally aggressive lesion
 Recurrence rate is high (71%)
 Malignant transformation has been reported
184

185. ENAMELOMA
185
Enamel pearl

186.  Small focal excessive mass of enamel
(ectopic nodule) on the surface of a
tooth root
186

187.  At furcation of roots or near the CEJ
 Maxillary molars > mandibular molars
 Asymptomatic
 Higher incidence in Mongoloid and
Eskimo populations
187

188. ETIOPATHOGENESIS
localised bulging of the odontoblastic layer
↓
prolonged contact between HERS and the
developing dentin
↓
inductive influence
↓
formation of enamel
188

189. Well-defined circular
radio-opaque nodule
189

190. 190

191.  May consist purely of
enamel; may also contain
underlying dentin and
pulp tissue
191

192. Potential complications:
 Weak periodontal attachment; attachment
by hemidesmosomes
 Area of stagnation that favours plaque
retention and improper cleansing
 Enamel pearl may sometimes contain vital
pulp tissue
192

193. ODONTOGENIC FIBROMA
 Peripheral Odontogenic Fibroma
 Central Odontogenic Fibroma
193

194. PERIPHERAL ODONTOGENIC FIBROMA
 Peripheral ossifying fibroma
 Calcifying fibrous epulis
194

195. CLINICAL FEATURES
 Rare lesion
 2nd- 7th decades of life
 Mandible > maxilla (facial gingiva)
 Slow growing lesions
 Size: 0.5cm - 1.5cm
 Firm, sessile gingival mass between the
teeth, causing displacement of teeth
195

196. HISTOPATHOLOGICAL FEATURES
 Cellular fibrous connective tissue
parenchyma
 Non-neoplastic, epithelial islands, strands
and cords of cuboidal / columnar
odontogenic epithelium (sometimes
vacuolated)
 Calcified tissue resembling bone / osteoid,
dentin / osteo-dentin may be seen
196

197. 197

198. 198

199. 199

200. CENTRAL ODONTOGENIC FIBROMA
 Uncommon central lesion
200

201. THREE BASIC CONCEPTS REGARDING
THE TUMOUR :
 Lesion around the crown of an unerupted
tooth resembling a dentigerous cyst
 Lesion of fibrous connective tissue with
scattered islands of odontogenic epithelium
 Fibroblastic neoplasm containing varying
amounts of odontogenic epithelium and
calcified material resembling dysplastic
dentin / cementum
201

202. CLINICAL FEATURES
 Age: 1st – 8th decades (mean age: 40 years)
 Female >males
 Mandible > maxilla
 Maxilla – (lesions located anterior to I molar)
 Mandible – (lesions located posterior to I molar)
 Asymptomatic
 May be associated with an unerupted tooth
202

203. RADIOGRAPHIC FEATURES
 Smaller lesions:
 well-defined unilocular radiolucencies
 larger lesions ￫ multilocular
 Lesions are seen in the peri-radicular
area; may cause root resorption
203

204. 204

205. HISTOPATHOLOGICAL FEATURES
 Simple COF
 WHO-type COF
205

206. SIMPLE COF:
 Tumour mass composed of mature collagen
fibres with stellate fibroblasts in a whorled
pattern
 Small islands / nests of inactive odontogenic
epithelium
206

207. 207
Simple type COF

208. WHO-TYPE COF:
 Composed of mature, fairly cellular fibrous
connective tissue with collagen fibers
arranged in interlacing bundles
 Long strands / isolated nests of odontogenic
epithelium
 Calcifications composed of cementum-like
material / dentinoid
208

209. 209
WHO-type COF

210. 210
WHO-type COF

211. 211

212. ODONTOGENIC MYXOMA
 Tumour which arises from the
mesenchymal portion of tooth germ
212

213. CLINICAL FEATURES
 2nd and 3rd decade of life;
(rare before age of 10 years or after 50)
 Males = Females
 Mandible > Maxilla
 Usually asymptomatic
 Rare lesions expand the bone and may
cause destruction of cortex
213

214. RADIOGRAPHIC FEATURES
 Unilocular / multilocular radiolucent lesion
 May have a mottled appearance
 May cause displacement / resorption of teeth
 The radiolucent area may contain thin wispy
trabeculae of residual bone arranged at right
angles to one another
 ‘Tennis-racket’ / ‘step-ladder’ appearance
214

215. 215

216. 216

217. 217

218. HISTOLOGICAL FEATURES
 Loosely arranged spindle-shaped and
stellate cells with long fibrillar processes
 Myxoid intercellular substance with few
collagen fibrils
 The ground substance contains two acid
mucopolysachharides
(↑ hyaluronic acid; ↓ chondroitin sulfate)
218

219. 219

220. 220

221. 221

222.  Tumour cells exhibit high alkaline
phosphatase and lactate dehydrogenase
activity
 Ultrastructural studies show two types of
cells
 Pale cells (represent secretory cells; synthesis of
mucopolysaccharide)
 Dark cells (contain crystallised collagen fibrils)
222

223. TREATMENT
 Curettage, resection.
 Recurrence rate 25%
 Risk of malignant transformation to
myxosarcomas
223

224. 224