Odontogenic Tumours - ameloblastoma Flashcards
Whee o of odontogenic tumors originate?
Remanat of toot forming tissues
Ordontogenic tumours benign?
Yes and do not metastasise
Odontogenic tumors cause bone destruction?
some are locally invasive and cause bone
destruction.
Name the epithelial without odontogenic mesenchymal?
Ameloblastoma (all types)
* Squamous odontogenic tumour
* Calcifying epithelial odontogenic tumour
* Adenomatoid odontogenic tumour
Name the Epithelial with odontogenic mesenchyme
(mixed)?
- Odontoma
- Ameloblastic fibroma
- Primordial odontogenic tumour
- Dentinogenic ghost cell tumour
Name the mesenchymal benign odontogenic tumours?
- Odontogenic fibroma
- Odontogenic myxoma
- Cementoblastoma
- Cemento-ossifying fibroma
Name the malignant odontogenic tumours?
- Sclerosing odontogenic carcinoma
- Ameloblastic carcinoma
- Clear cell odontogenic carcinoma
- Ghost cell odontogenic carcinoma
- Primary intraosseous carcinoma, NOS
- Odontogenic carcinosarcoma
- Odontogenic sarcomas
What type of tnour is ameloblastoma?
Benign but locally invasive
Ameloblastoma rare or common?
Rare
Several variants but the most common is the
conventional/ solid/multi-cystic ameloblastoma
Clinical presentation of ameloblastoma?
Clinical presentation:
* Most cases between 30 and 60, and rare before
20.
* Geographic variations.
* Mainly in the jaws, rarely in sinonasal cavities.
* 80% in the mandible (70% in the molar region and
ascending ramus). Population variation.
* In the maxilla, mainly in the molar region.
Ameloblastoma slow or fast growing tumour?
Slow growing tumour
Ameloblastoma symptomatic?
Asymptomatic at early stages
Growth of ameloblastoma?
Slow growing tumour, asymptomatic at early
stages.
* Gradually increasing facial deformity and
expansion of jaw bones.
* Perforation of bone and extension into soft
tissues in late stages.
* Expansion into the sinus and may invade skull
base.
* Loose teeth due to root resorption.
Radiography of ameloblastoma?
- Unilocular or multilocular radiolucency
resembling a cyst. - Scalloped borders are sometimes seen.
- An unerupted tooth may be present.
- Resorption of the roots of adjacent teeth is
common.
Soap bubble appearance
Multilocular
Unilocular
Histopathology of ameloblastoma?
- Macroscopically, ameloblastoma may show
extensive cystic changes. - Thickened mural areas must be sampled by
biopsy to establish the diagnosis. - Microscopically, many variations
Variations of ameloblastoma?
Follicular and plexiform are the two main patterns.
Can 2 forms of ameloblastoma exist n tumour?
Yes, can coexist
They describe the distribution of the odontogenic
epithelium within the stroma in the tumour.
Follicular pattern of ameloblastoma?
- The odontogenic
epithelium is arranged in
islands (follicles) within
fibrous stroma. - The follicles resemble the
enamel organ. - Central mass resembling
the stellate reticulum
surrounded by columnar
ameloblast like cells
(reversed polarity).
Can get cystic formation
What can happen in the stellate area of ameloblastoma? (Follicular)
Cystic breakdown
Granular cell changes
Squamous metaplasia (acanthomatous)
Histopathology of plexiform pattern (ameloblastoma)?
Plexiform Pattern:
* The epithelium is arranged
as a tangled network of
anastomosing strands and
irregular masses.
* Same cell layers as the
follicular pattern.
* Cyst formation due to stromal degeneration.
Behaviour of ameloblastoma?
Benign but invasive - fade narrow spaces in bone
- Intraosseous tumours are locally invasive with islands of the tumour
invading the marrow spaces. - High recurrence rates (50-90%). Long- term follow- up is mandatory
because recurrence has been found after more than 10 years. - Pulmonary metastasis.
- Ameloblastic carcinoma.
Recurrent rate of ameloblastoma?
High recurrent - 50-90%
Ameloblastoma malignant or locally invasive?
Locally invasive
Management of ameloblastoma?
- Management:
- Biopsies may show mainly cystic areas, in these cases, it is necessary to
correlate the biopsy and imaging appearances to reach a definitive
diagnosis. - Current treatment aims at achieving complete excision with a small margin
of uninvolved tissue. - In some cases a more conservative approach may be adopted.
- Radiotherapy and chemotherapy are not advocated.
Rare variant of ameloblastoma?
Desmoplastic ameloblastoma
Where is the desmoplastic amleoblasoma found?
Anterior mandible and maxilla
Desmoplastic ameloblastoma?
- Most frequently in the anterior mandible and maxilla.
- Similar age range to conventional ameloblastoma.
- Radiographs show a distinctive appearance
consisting of a mottled, diffuse, mixed radiodense
and radiolucent lesion, often associated with tooth
displacement and/ or resorption. - Treatment is similar to that of conventional
ameloblastoma— complete excision.
Microscpically desmoplastic ameloblastoma?
abundant stromal component with
compressed islands of odontogenic epithelium that
resemble ameloblastoma but are jagged in outline.
Metaplastic bone trabeculae, microcytic change, and
myxoid areas may be present.
Clinical presentation of uni cystic ameloblastoma?
- Younger age group than conventional ameloblastoma.
- Posterior Mandibular (over 90% of the cases)
Radiographing presentation of unicystic ameloblastoma?
- Well defined unilocular radiolucency that looks like a cyst.
- Many cases are associated with an unerupted tooth,
especially third molars.
3 variants of unicystic ameloblastoma?
- Luminal type: the cyst is lined by ‘ameloblastomatous’
epithelium. - Intra-luminal type: the cyst has projections of plexiform
ameloblastoma into the central cystic cavity. - Mural type: the ameloblastomatous cyst lining shows
complex budding and invasion of the cyst wall.
Recurrence of mural type unicystsic ameloblastoma?
High risk
Management of unicystic ameloblastoma?
- The luminal and intra- luminal types show no invasion of the
cyst wall and the majority are eradicated by enucleation. - The mural type has a risk of recurrence and treatment is the
same as for conventional ameloblastoma; complete excision.
Clinical presentation of perineal ameloblastoma?
- Presents mostly in the gingiva as a red,
sometimes papillary, mucosal patch. - May be raised
- Although there may be ‘saucerization’
of the underlying bone, the tumour is
entirely extra- osseous
Bone not effected, completely inside soft tissue
Histopathology of peripheral ameloblastoma?
May resemble conventional ameloblastoma.
* Mainly baseloid cells.
* The neoplasm appears to originate from the surface
epithelium.
*The oral counterpart of basal cell carcinoma?
Management of peripheral ameloblastoma?
- Local excision, often involving a rim resection or block of
underlying alveolar bone. - In rare cases, can de- differentiate and give rise to
ameloblastic carcinoma that invades the underlying jaw.
Pathogenesis of ameloblastoma? (6)
- Residues of the dental lamina (majority).
- Lining of the dentigerous cyst (Unicystic ameloblastoma).
- Basal layer of the oral epithelium (peripheral ameloblastoma).
- Epithelial rests of Malassez.
- Reduced enamel epithelium.
- The cells express amelogenin, but with no enamel or dentine
formation they are considered preameloblasts.
Ant structure with ameloblasts or preameloblasts can form ameloblastoma
When could metastasis occur?
No real evidence
- An ameloblastoma that has metastasized despite its benign
histopathological appearance. - Lung
- Aspiration, surgical implantation as causes
- Debate about classification
It is just locally invasive
New ameloblastoma?
Adenoid ameloblastoma
