Classification of ODONTOGENIC TUMORS & AMELOBLASTOMA According to WHO Classification System (2005)

1. Dr. V. Mukesh Krishna

2. Lesions derived from :
Epithelial
Ectomesenchymal
Mesenchymal elements ( part of the tooth forming apparatus )
Found exclusively within the :
Maxillofacial skeleton (intraosseous or centrally located)
Soft tissue (gingiva) overlying tooth-bearing areas or
Alveolar mucosa in edentulous regions (extraosseous or peripherally located).
May be generated at any stage in the life of an individual

3. A. MALIGNANT TUMORS :
1) Odontogenic Carcinomas
2) Odontogenic Sarcomas
B. BENIGN TUMORS :
1) Odontogenic epithelium with mature, fibrous stroma without odontogenic
ectomesenchyme
2) Odontogenic epithelium with odontogenic ectomesenchyme, with or without hard tissue
formation
3) Mesenchyme and/or odontogenic ectomesenchyme with or without odontogenic
epithelium
C. BONE-RELATED LESIONS :
D. OTHER TUMORS :

4. 1. ODONTOGENIC CARCINOMAS
a) Malignant Ameloblastoma
b) Ameloblastic Carcinoma: Primary Type
c) Ameloblastic Carcinoma: Secondary Type (Dedifferentiated), Intraosseous
d) Ameloblastic Carcinoma: Secondary Type (Dedifferentiated), Peripheral
e) Primary Intraosseous Squamous Cell Carcinoma: Solid Type
f) Primary Intraosseous Squamous Cell Carcinoma: Keratocystic Odontogenic Tumour
g) Primary Intraosseous Squamous Cell Carcinoma Derived From An Odontogenic Cyst
h) Clear Cell Odontogenic Carcinoma
i) Ghost Cell Odontogenic Carcinoma
A. MALIGNANT TUMORS

5. 2. ODONTOGENIC SARCOMAS
a) Ameloblastic Fibrosarcoma (Ameloblastic Sarcoma)
b) Ameloblastic Fibrodentinosarcoma and Fibro-odontosarcoma
A. MALIGNANT TUMORS

6. 1. ODONTOGENIC EPITHELIUM WITH MATURE, FIBROUS STROMA
WITHOUT ODONTOGENIC ECTOMESENCHYME
a) Ameloblastoma: Solid/Multicystic Type
b) Ameloblastoma: Extraosseous/Peripheral Type
c) Ameloblastoma: Desmoplastic Type
d) Ameloblastoma: Unicystic Type
e) Squamous Odontogenic Tumour
f) Calcifying Epithelial Odontogenic Tumour (Pindborg Tumour)
g) Adenomatoid Odontogenic Tumour
h) Keratocystic Odontogenic Tumour
B. BENIGN TUMORS

7. 2. ODONTOGENIC EPITHELIUM WITH ODONTOGENIC ECTOMESENCHYME,
WITH OR WITHOUT HARD TISSUE FORMATION
a) Ameloblastic Fibroma
b) Ameloblastic Fibrodentinoma (Dentinoma)
c) Ameloblastic Fibro-odontoma
d) Odontoma
• Odontoma: Complex Type
• Odontoma: Compound Type
e) Odontoameloblastoma
f) Calcifying Cystic Odontogenic Cyst
g) Dentinogenic Ghost Cell Tumour
B. BENIGN TUMORS

8. 3. MESENCHYME AND/OR ODONTOGENIC ECTOMESENCHYME WITH OR
WITHOUT ODONTOGENIC EPITHELIUM
a) Odontogenic Fibroma
b) Odontogenic Myxoma / Myxofibroma
c) Cementoblastoma
B. BENIGN TUMORS

9. a) Ossifying Fibromas (Cemento-ossifying Fibroma)
b) Fibrous Dysplasia
c) Osseous Dysplasias
• Cemento-osseous Dysplasia
d) Central Giant Cell Lesion (Granuloma)
e) Cherubism
f) Aneurysmal Bone Cyst
g) Simple Bone Cyst
C. BONE-RELATED LESIONS
D. OTHER TUMORS
a) Melanotic Neuroectodermal Tumour Of Infancy

10. Ameloblastoma {amel – enamel, blastos -germ} is rare benign tumour of
odontogenic epithelium. (ameloblasts)
“ADMANTINOMA”
ROBINSON : Unicentric, Non functional, Intermittent in growth, anatomically
benign & clinically persistent tumour

11. Most common Neoplasm of the Jaw
CLINICAL FEATURES :
• Age : 3rd to 5th Decade
• Sex : No predilection
• Site : Mandible (80%) > Maxilla
CHARECTERS :
• Asymptomatic & Slowly Growing
• Later stage > Nerve involvement > Sensory changes of the
lower lip > Pain of secondary infection.
• Large persistent lesion >Fluctuation “ Eggshell Crackling”
Radiographic Appearences :
• Multilocular Radiolucent ( Honeycomb / Soap Bubble )
• Unilocular Radiolucent a/w Impacted tooth

13. 1. Basal Layer of Oral Epithelium
2. Dental Lamina or its Remnants
3. Enamel origin or its Remnants
4. Epithelial Lining of a Follicular Cyst

14. MACROSCOPIC :
• Solid or Cystic
• Traversed by Bony Ridges
MICROSCOPIC :
• Epithelium forming this neoplasm resembles Enamel origin
• Surrounding Fibrous Stroma vary in Quantity & Cellularity
• Stroma is Collagenous with Few Cells / Abundantly Cellular Stroma
Main HISTOLIGICAL PATTERNS :
1. Follicular
2. Plexiform

15. A. The Solid / Multicystic / Intraosseous type. (conventional)
B. The Unicystic type
C. Peripheral type (extraosseous)
D. Malignant Ameloblastoma.
E. Pituitary Ameloblastoma (craniopharyngeoma / rathkes pouch tumour)

16. 1. SOLID FORM :
i. Peripheral Layer : Cuboidal or Columnar Cells ( Ameloblasts )
ii. Central Mass : Polyhedral Cells ( Stellate Reticulum like Cells )
2. CYSTIC FORMATION :
i. Microcystic : Start of degeneration : Microcysts in Central mass of follicle. Peripheral
layer – Ameloblast like > Low Cuboidal due to pressure of cystic fluid.
ii. Macrocystic : Microcysts fuse to form Larger Cyst. Peripheral cells > Flattened
3. ACANTHOMATOUS :
Areas of Sq. Metaplasia ( High Recurrence & Malignancy )
Central cells > Squamous
Keratin formation ( Kerato-Ameloblastoma )

17. 4. GRANULAR AMELOBLASTOMA :
Central cells > Granular change ( Rare )
Larger, Cuboidal, Rounded, Columnar with Neclei pushed against cell wall+ coarse
eosinophilic granules ( Phago-Lysososmes )
5. BASAL CELL AMELOBLASTOMA : Cuboid Peripheral Cells & Compact Central
6. HYALINIZED C.T. Stroma : Hyalizination of stroma adjacent to epithelial follicle
7. DESMOPLASTIC AMELOBLASTOMA : Consists of cellular loose C.T. /
Collagenous

19. The Tumour Epithelium : Irregular intercommunicating anastomosing strands (
Discrete islands in Follicular variant )
1. SOLID PLEXIFORM :
Bounded by a layer of Columnar or Cuboidal Cells ( Ameloblastic like cells ) + surrounded
by Stellate Reticulum like cells
2. CYSTIC PLEXIFORM :
Cystic degeneration of C.T. Stroma > Stromal Cysts
Stroma degeneration > Spaces > Blood + Epithelial strands lining > Hemangio-AB
3. PLEXIFORM UNICYSTIC : Recent entity : same as solid type ; low recurrence rate &
treated without safety margin ( enucleation )

22. THANK YOU