Odontogenic tumours Flashcards
Odontogenic tissues (8)
Epithelium -oral epithelium -dental lamina -enamel organ -reduced enamel epithelium -rests of Malassez Mesenchyme -dental papilla -dental follicle -periodontal ligament
Remnants of odontogenic tumours and their possible consequences (3)
Hertwig’s root sheath –> radicular cysts
Reduced enamel epithelium –> dentigerous cysts
Dental lamina –> ameloblastoma, ameloblastic fibroma, CEOT, keratocyst, gingival cysts
Odontogenic tumours (3)
Most present as as radiolucent lesions
Some may contain calcifications
Most often at angle of mandible
Classification of odontogenic tumours (4)
Benign: -odontogenic epithelium alone -odontogenic epithelium and odontogenic mesenchyme +/- dental hard tissues -odontogenic mesenchyme alone Malignant: -carcinomas and sarcomas
Epidemiology of odontogenic tumours (4)
Odontogenic neoplasms are rare
Less than 1% of all tumours
Ameloblastoma is most common neoplasm
Odontomes are not neoplasms
Ameloblastoma epidemiology (3)
Benign, but locally destructive
Age 30-50
80% in mandible, most at the angle
Ameloblastoma: clinical (4)
Often asymptomatic
Bucco-lingual expansion
Root resorption or displaceent
Uni- or multi-locular radiolucency
Ameloblastoma - subtypes (3)
- Conventional type: intra-osseus (85%)
- follicular
- plexiform (many tumour contain both patterns) - Unicystic: intra-osseus (14%)
- Peripheral: extra-osseus/ gingiva (1%)
The follicular pattern of ameloblastoma (histology) (4)
Columnar ameloblast like cells at the periphery
Stellate reticulum-like area in the centre
The epithelium resembles the enamel organ
Cysts form in stellate reticulum-like areas
The plexiform pattern of ameloblastoma (histology) (3)
Columnar ameloblast like cells forming cords
Little or no stellate reticulum-like areas
Cysts form in stroma
Unicystic ameloblastoma types (literature supporting this is very poor) (4)
True unicystic ameloblastomas - can be ennucleated:
-luminal type
-intraluminal type
Variants of conventional ameloblastoma - should be excised with a margin (2)
-mural type
-multicystic type
Management of ameloblastoma: conventional ameloblastoma (3)
Requires excision (with margins) Reconstruction Maxilla can be very challenging
Management of ameloblastoma: true uicystic (very rare) (2)
Enucleation
Careful follow up
Adenomatoid odontogenic tumour epidemiology and cure (4)
Benign, does not recur, probably a hamartoma
Age 10-20, F>M
Most often in maxilla
Enucleation sufficient to cure
Adenomatoid odontogenic tumour radiology (2)
Radiolucency often around a tooth crown, may have calcifications
Differential diagnosis: dentigerous cyst
Adenomatoid odontogenic tumour histology (2)
Epithelial cells forming sheets and duct-like structures
Calcification common
Calcifying epithelial odontogenic tumour (‘Pindborg tumour’) epidemiology (3)
Benign but locally destructive
Age 10-60
2/3 in mandible, molar region +/- u/e tooth
Calcifying epithelial odontogenic tumour (‘Pindborg tumour’) radiology (1)
Radiolucency with speckled calcifications
Calcifying epithelial odontogenic tumour (‘Pindborg tumour’) histology (2)
Composed of ‘pleomorphic’ epithelium with calcifications, ‘dentinoid’ and amyloid
Cuboidal cells with ‘prickles’
Calcifying epithelial odontogenic tumour (‘Pindborg tumour’) treatment (1)
As for ameloblastoma
Is the odontogenic keratocyst a tumour? (3)
Clinical evidence -pattern of recurrence -link to NBCCS (gorlin-Goltz) Genetic evidence -PTCH mutations (9q22-31) -clonality? In 2005, the WHO changed the name to keratocystic odontogenic tumour (KCOT): this was reversed in the 2017 classification
Group 2: Odontogenic epithelium and
Odontogenic mesenchyme +/- dental hard tissue (3)
Ameloblastic fibroma
Dentinogenic ghost cell tumour
Odontomes - covered in an earlier lecture
Ameloblastic fibroma epidemiology (3)
Benign
Age <20
Often in mandible
Ameloblastic fibroma radiology (2)
Well defined radiolucency
80% associated with unerupted tooth
Ameloblastic fibroma histology
Branching cords and islands of epithelium resembling enamel organ or dental lamina
Characteristic fine cellular stroma
Dentinogenic ghost cell tumour epidemiology (4)
Benign Very rare Age most 40.60 M>F Mandible or maxilla
Dentinogenic ghost cell tumour radiology (1)
Radiolucency, may have calcifications
Dentinogenic ghost cell tumour histology (3)
Epithelium resembling ameloblastoma
Ghost cells and dentine
Overlap with calcifying odontogenic cyst
Odontomes (4)
Hamartomas: benign malformations
Age: up to 20 (developing dentition)
May be mmandible or maxilla
Radiolucency containing tooth-like structure
Compound odontome (5)
- Twice as common as complex odontome
- Maxilla > Mandible
- Incisor / Canine regions
- Small and non-aggressive
- A collection of ‘denticles’ (mini-teeth)
Complex odontome (5)
• Mandible > Maxilla • Premolar / Molar regions • 10 – 25 year age group • Often a missing tooth in the arch • A fused mass of haphazardly arranged tooth tissues but normal morphogenetic relations are preserved
Group 3: odontogenic mesenchyme alone (3)
- Myxoma/myxo-fibroma
- Odontogenic Fibroma
- Cementoblastoma
Myxoma and fibromyxoma epidemiology (3)
Benign but locally destructive
10-30 years
Most in mandible
Myxoma and fibromyxoma: clinical (1)
Slow growing painless swelling
Myxoma and fibromyxoma radiology (3)
Uni- or multi-locular radiolucency
‘Soap-bubble’ appearance
Root displacement or resorption
Myxoma and fibromyxoma histolgoy (2)
Triangular/ stellate cells in loose myxoid stroma
Myxoma and fibromyxoma treatment (1)
As for ameloblastoma
Odontogenic fibroma (4)
• Wide age range, F
Odontogenic fibroma histolgoy (2)
• mature fibrous tissue,
• variable amounts of inactive
odontogenic epithelium
Cementoblastoma epidemiology (3)
Benign
Age 10-40
Usually mandible, affecting molar teeth
Cementoblastoma radiology (2)
Radiopaque lesion attached to tooth root
Cementoblastoma histology (2)
Sheets of cementum and osteoid in a mosaic pattern; many plump cementoblasts
Resembles osteoblastoma
Malignant odontogenic tumour (3)
Very rare Odontogenic carcinomas • Ameloblastic carcinoma • Primary intra-osseous carcinoma • Clear cell odontogenic carcinoma • Malignant variants of other tumours/cysts Odontogenic sarcomas
