Odontogenic Tumours Flashcards
What epithelium can odontogenic tissues arise from?
Epithelium: Oral epi Dental lamina Enamel organ Reduced enamel epi Rests of malassez
Mesenchyme:
- Dental papilla
- Dental follicle
- Periodontal ligament
What arises from hertwig’s root sheath?
Radicular cysts
What arises from the reduced enamel epithelium?
Dentigerous cysts
What arises from the dental lamina?
Ameloblastoma Ameloblastic fibroma CEOT Keratocyst Gingival crest
What are odontogenic tumours most present as? Where?
Most present as radiolucent lesions
Some may contain calcifications
Most often at angle of mandible as arise from dental lamina = 8 is last use of dental lamina
Classification of odontogenic tumours?
Benign
- Odontogenic epithelium alone = GROUP 1
- Odontogenic epithelium and odontogenic mesenchyme +/- dental hard tissues
- Odontogenic mesenchyme alone
Malignant
- Carcinomas and sarcomas
Epidemiology of odontogenic tumours?
Odontogenic neoplasms = rare
Less than 1% of all oral tumours
Ameloblastoma is most common neoplasm
Odontomes are NOT neoplasms
What makes up group 1: odontogenic epithelium alone?
Ameloblasoma
Adenomatoid odontogenic tumour (AOT)
Calcifying epithelial odotogenic tumour (CEOT)
Squamous odontogenic tumour (SOT)
Ameloblastoma features?
Benign but locally destructive
Uni or multi-locular radiolucency
Ameloblastoma epidemiology?
Epidemiology:
- Age: 30-50
- 80% in mandible, most at angle
Clinical presentation of ameloblastomas?
Clinical:
- Often asymp until obstruction of nerves
- Bucco-lingual expansion
- Root resorption or displacement
Uni or multi-locular radiolucency
Medial pterygoid muscle attachment onto pterygoid plates at lingual side of mandible - muscle can be affected
Ameloblastoma subtypes?
- Conventional types: intra-osseous
- Follicular
- Plexiform
= 85% - Unicystic: intra-osseous 14%
- Younger patients 10-20
- Mainly posterior mandible - Peripheral: extra-osseous/gingiva 1%
Ameloblastoma histology?
Follicular pattern: Columnar ameloblast like cells at the periphery with reverse polarity
Stellate reticulum like area in the centre
Epithelium resembles the enamel organ and there are islands and trabeculae of epithelial cells in a CT stroma
Cysts form in stellate reticulum like areas
Plexiform pattern:
- Columnar ameloblasts like cells forming cords
- Epithelium forms strands and trabeculae of small, darkly staining epithelial cells in a CT stroma with few cells
- Little or no stellate reticulum like areas
- Cysts form in stroma
Management of ameloblastoma?
Diagnosis via biopsy
Conventional ameloblastoma:
- Requires excision (1-2cm with margins of normal bone to remove any extension into the surrounding bone)
- Reconstruction if removing part of mandible
- Maxilla can be very challenging: Bones are thinner and are weak barriers to spread. Can invade up into the orbit ad the brain.
True unicystic (v rare, types 1 and 2)
- Enucleation but risk of recurrence
- Careful follow up
Features of adenomatoid odontogenic tumour? How to treat?
Benign, does not recur, probably a hamartoma
Enucleation sufficient to cure - do not reoccur
Epidemiology of adenomatoid odontogenic tumour?
Age 10-20, F>M
Most often in maxilla, especially unerupted maxillary canine
Radiological appearance of of adenomatoid odontogenic tumour?
Radiolucency often around a tooth crown, may have calcifications - fine and speckled like a snow storm radiopaque appearance
Histology of adenomatoid odontogenic tumour?
Epithelial cells forming sheets and duct like structures
Calcified material a bit like dentine
Differential diagnosis of of adenomatoid odontogenic tumour?
Dentigerous cyst
Calcifying epithelial odontogenic tumour (Pindborg tumour) features?
Benign but locally destructive
Calcifying epithelial odontogenic tumour epidemiology?
10-60
2/3 in mandible, molar region +/- unerupted tooth
Symptoms lacking until a swelling appears
Calcifying epithelial odontogenic tumour radiological appearance?
Radiolucency with speckled calcifications, increasing radiopacity as it matures
Poorly defined margins
Calcifying epithelial odontogenic tumour histology?
Composed of pleomorphic epithelium with calcifications, dentinoid and amyloid
Enamel matrix material which may calcify
Cuboidal cells with prickles
Large flat cells with a single nucleus in them
Calcifying epithelial odontogenic tumour treatment?
Like ameloblastoma - surgical removal with margins, reconstruction or enucleation
Is the odontogenic keratocyst a tumour?
Clinical evidence:
- Pattern of recurrence
- Link to NBCCS (gorlin goltz)
Genetic evidence
- PTCH mutations (9q22-31)
- Clonality evidence?
Group 2 odontogenic epithelium and odontogenic mesenchyme +/- dental hard tissues types?
Ameloblastic fibroma
Dentinogenic ghost cell tumour
Odontomes
Benign or malignant - ameloblastic fibroma?
Benign
Ameloblastic fibroma epidemiology?
<20
Often in mandible
Ameloblastic fibroma radiology?
Well defined radiolucency
80% associated with unerupted tooth
Ameloblastic fibroma histology?
Branching cords and islands of epithelium resembling the enamel organ or dental lamina
Characteristic fine cellular stroma
Dentinogenic ghost cell tumour features?
Benign
Dentinogenic ghost cell tumour epidemiology?
V rare
40-60
M>F
Mandible or maxilla
Dentinogenic ghost cell tumour radiology?
Radiolucency, may have calcifications
Dentinogenic ghost cell tumour histology?
Epithelium resembling ameloblastoma Ghost cells (nuclei disappear leaving white spots) and dentine Overlap with calcifying odontogenic cyst
Odontomes features?
Hamartomas: benign malformations
Up to 20 yrs old (developing dentition)
May be mandible or maxilla
Radiolucency containing tooth like structures
Compound odontome features?
2X more common as complex odontome Maxilla>mandible Incisor/canine regions Small and non-aggressive A collection of denticles (mini teeth)
Complex odontome features?
Mandible > maxilla Premolar/molar regions 10-25yr age group Often a missing tooth in the arch A fused mass of haphazardly arranged tooth tissues but normal morphogenic relations are preserved Enucleated and removed = do not recur
Group 3 odontogenic mesenchyme alone types?
Myxoma/myxo-fibroma
Odontogenic fibroma
Cementoblastoma
Myxoma and fibromyxoma features?
Benign but locally destructive
Myxoma and fibromyxoma epidemiology?
10-30yrs
Most in mandible
Myxoma and fibromyxoma clinical features?
Slow growing, painless swelling
Myxoma and fibromyxoma radiology?
Uni or multi-locular radiolucency
Soap bubble appearance
Root displacement or resorption
Myxoma and fibromyxoma histology?
Triangular/stellate cells in loose myxoid stroma
Pale staining with spindle cells
Myxoma and fibromyxoma treatment?
As for ameloblastoma
- excision with a margin
Odontogenic fibroma features?
Wide age range M>F Md = Mx Central and peripheral types Most often unilocular radiolucency Histology: mature fibrous tissue, variable amounts of inactive odontogenic epithelium
Cementoblastoma?
Benign
10-40
Usually mandible, affecting molar teeth
Radiopaque lesion ATTACHED TO TOOTH ROOT
Histo:
Sheets of cementum and osteoid in a mosaic pattern, many plump cementoblasts
Resembles osteoblastoma
Malignant odontogenic tumours? Types?
V rare
Odontogenic carcinomas
- Ameloblastic carcinoma
- Primary intra-osseous carcinoma
- Clear cell odontogenic carcinoma
- Malignant variants of other tumours/cysts
Odontogenic sarcomas
