DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY

2. Odontogenic Tumors

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

4. 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 !!!

5. 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

6. 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

7. 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)

8. Ameloblastoma
• 2. extra-osseous (peripheral) 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

9. 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

10. 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

11. 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

12. 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

13. 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

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

15. 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)

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

17. Ghost cell odontogenic
carcinoma
• malignant counterpart of DGCT

18. 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

19. 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

20. 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

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

22. 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

23. 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

24. 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 !!!