1. Assoc. Professor Jan Laco, MD, PhD
Odontogenic Tumors
Assoc. Professor Jan Laco, MD, PhD

2. Causes of jaw swelling Odontogenic cysts Odontogenic tumors
Giant cell lesions
Fibro-osseous lesions
Primary (non-odontogenic) tumors of bone
Metastatic neoplasms
Chronic osteomyelitis

3. Odontogenic tumors
derived from epithelial, ectomesenchymal, mesenchymal elements of tooth forming apparatus
central (intraosseous)
maxillofacial skeleton
peripheral (extraosseous)
soft tissue - gingiva + alveolar mucosa
ethiology unknown, from some odontogenic cysts
RTG
uni-, multi-locular radiolucencies ~ cysts x radiopacities
!!! biopsy !!!

4. Odontogenic tumors 1. Epithelial ameloblastoma
squamous odontogenic tumor
calcifying epithelial odontogenic tumor
adenomatoid odontogenic tumor
2. Epithelial+mesenchymal
ameloblastic fibroma
odontoma
dentinogenic ghost cell tumor
primordial odontogenic tumor

5. Odontogenic tumors 3. Mesenchymal odontogenic fibroma
odontogenic myxoma
cementoblastoma
4. Carcinomas
ameloblastic carcinoma
primary intraosseous squamous cell carcinoma
clear cell odontogenic carcinoma
ghost cell odontogenic carcinoma
sclerosing odontogenic carcinoma
5. Odontogenic carcinosarcoma
6. Odontogenic sarcoma

6. Ameloblastoma benign x locally aggressive
1. solid / multicystic A (S/MA)
2nd most common odontogenic tumor
M ~ F, peak 30-50Y; RTG: multilocular cystic radiolucency
posterior mandible (70%) +  posterior maxilla ( skull)
spread through bone medullary spaces, cortex intact
Mi: follicular / plexiform pattern + fibrous stroma
islands of odontogenic epithelium (enamel organ-like)
basaloid, granular, acanthomatous variants, keratoA
anastomosing strands
recurrence (after 10Y) – long term RTG follow-up !!!
treatment: jaw resection with free margins (2 cm)

7. Ameloblastoma 2. extra-osseous (peripheral) A 3. unicystic A
~ S/MA x soft tissues over mandible, treat.: simple excision
older pts., M : F …1 : 2
3. unicystic A
2 peaks – 16Y (+ unerupted tooth) + 35Y (NO uner. tooth)
5-15% of all As, luminal x mural subvariants
not so aggressive as S/MA
diff. dg. from benign cysts !!!  biopsy (! inflammation)
treat.: luminal – simple excision x mural – acc. SMA
4. metastasizing ameloblastoma
dg. in retrospect according to behaviour not histology!!; lung

8. Ameloblastic carcinoma
1. primary
rare, China
posterior mandible
Mi: malignant appearance A
lung metastases
2. secondary (intra-, extraosseous)
A (long lasting)  AC
Mi: A + AC

9. Squamous odontogenic tumor
benign x locally aggressive
extremely rare
M > F, ~ 40Y
mandible (from squamous nests in periodontal ligaments ?)
Mi: well-differentiated squamous epithelium + fibrous stroma
dif. dg.: squamous cell carcinoma
squamous nests in wall of jaw cyst - RTG

10. Calcifying epithelial odontogenic tumor
benign x locally aggressive
„Pindborg´s tumor“ (1955)
M ~ F, ~ 40Y; RTG: radiolucency + opacity
mandible (premolar/molar)
Mi: sheets of pleomorphic epithelial cells x mitoses absent
amyloid  concentric calcifications
recurrence (20%)
treatment: according SMA
diff. dg.: poorly differentiated carcinoma

11. Adenomatoid odontogenic tumor
benign, hamartoma ???
M : F …1 : 2; peak ~ 15-30Y
anterior maxilla !!!; RTG: ~ odontogenic cyst
sometimes around crown of unerupted tooth
dif. dg.: follicular (dentigerous) cyst
Mi: solid nodules – epithelial cells
nests, tubular structures + eosinophilic material
calcifications
treatment: enucleation

12. Ameloblastic fibroma
benign
rare, ~ 15Y
posterior mandible; RTG: uni- / multilocular cyst
Mi: ~ A + stroma ~ dental pulp
treatment: enucleation
diff. dg.: ameloblastoma – different treatment !!!
Ameloblastic fibrodentinom/fibroodontoma
developmental stages of odontoma

13. Odontogenic sarcomas 1. ameloblastic fibrosarcoma
malignant counterpart of ameloblastic fibroma
2. ameloblastic fibrodentino-, fibroodonto-sarcoma
AFS + dentin / dentin + enamel
no prognostic significance

14. Odontoma true tumor (WHO), hamartoma ??? most common odontogenic tumor
children, adolescents
treatment: enucleation
1. complex type
posterior mandible, encapsulated
Mi: haphazardly enamel + dentin + cementum
2. compound type
anterior maxilla, encapsulated
numerous tooth-like structures (odontoids)

15. Dentinogenic ghost cell tumor
 solid variant of calcifying odontogenic cyst
canine-first molar area
locally aggressive

16. Ghost cell odontogenic carcinoma
malignant counterpart of DGCT

17. Odontogenic fibroma benign, rare, somewhat controversial entity
F : M … 3 : 1, ~ 40Y
mandible : maxilla … 6.5 : 1
Mi: epithelium-rich x epithelium-poor
odontogenic epithelium + fibrous stroma
dif. dg.: dental follicle - RTG

18. Odontogenic myxoma / myxofibroma
benign
3rd most common odontogenic tumor
F > M, ~ 30Y
molar mandible
maxilla (maxillary sinus obliteration)
spread through medullar bone space
Mi: myxoid stroma + stellate cells
recurrence (25%) !!!
treatment: wide excision
dif. dg.: dental pulp tissue

19. Cementoblastoma benign M ~ F, ~ 20Y first molar of mandible
RTG: radiopaque mass + connection with tooth root !!
Mi: acellular cementum-like material bordered by plump cells without atypia
fibrovascular tissue
dif. dg.: osteoblastoma, osteosarcoma
recurrence !!!
treatment: enucleation + tooth extraction

20. Primary intraosseous squamous cell carcinoma
NO initial connection to oral mucosa
solid
from KOT
from other odontogenic cysts
metastases - LN and lungs

21. Clear cell odontogenic carcinoma
WHO (1992) – benign x WHO (2005) - malignant
F > M, ~ 60Y
mandible
Mi: cells with clear cytoplasm + fibrous stroma
aggressive behaviour, recurrence
metastases – LN, lung, bone, …
t(12;22) … EWSR1-ATF1

22. Melanotic neuroectodermal tumor of infancy
= melanotic progonoma, retinal anlage tumor, …
very rare (350 cases), neural crest ???
infants (80% < 6th month, 95% < 1st year)
F : M …2 : 1
maxilla (70%), mandible (10%), skull (10%)
rapidly growing pigmented mass, 3-4 cm
microscopy
small neuroblastic cells (granules), synaptophysin +
melanin-containing cells (melanosomes), CK, HMB45 +
local recurrence + metastases (7%) to LN, liver, bone

23. !!! every lesion, incl. cysts, must be microscopically examined !!!
Take home message
odontogenic tumors – rare x do exist
NOT only ameloblastoma
although benign x locally aggressive
DON´T rely on RTG itself
secondary inflammation may obscure the true nature of some lesions on microscopy
local recurrence (up to decades!) – long-term follow up
!!! every lesion, incl. cysts, must be microscopically examined !!!