Odontogenic Tumours - ameloblastoma

Question 2

Whee o of odontogenic tumors originate?

Answer 2

Remanat of toot forming tissues

Question 3

Ordontogenic tumours benign?

Answer 3

Yes and do not metastasise

Question 4

Odontogenic tumors cause bone destruction?

Answer 4

some are locally invasive and cause bone
destruction.

Question 5

Name the epithelial without odontogenic mesenchymal?

Answer 5

Ameloblastoma (all types)
* Squamous odontogenic tumour
* Calcifying epithelial odontogenic tumour
* Adenomatoid odontogenic tumour

Question 6

Name the Epithelial with odontogenic mesenchyme
(mixed)?

Answer 6

• Odontoma
• Ameloblastic fibroma
• Primordial odontogenic tumour
• Dentinogenic ghost cell tumour

Question 7

Name the mesenchymal benign odontogenic tumours?

Answer 7

• Odontogenic fibroma
• Odontogenic myxoma
• Cementoblastoma
• Cemento-ossifying fibroma

Question 8

Name the malignant odontogenic tumours?

Answer 8

• Sclerosing odontogenic carcinoma
• Ameloblastic carcinoma
• Clear cell odontogenic carcinoma
• Ghost cell odontogenic carcinoma
• Primary intraosseous carcinoma, NOS
• Odontogenic carcinosarcoma
• Odontogenic sarcomas

Question 9

What type of tnour is ameloblastoma?

Answer 9

Benign but locally invasive

Question 10

Ameloblastoma rare or common?

Answer 10

Rare

Several variants but the most common is the
conventional/ solid/multi-cystic ameloblastoma

Question 11

Clinical presentation of ameloblastoma?

Answer 11

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.

Question 12

Ameloblastoma slow or fast growing tumour?

Answer 12

Slow growing tumour

Question 13

Ameloblastoma symptomatic?

Answer 13

Asymptomatic at early stages

Question 14

Growth of ameloblastoma?

Answer 14

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.

Question 15

Radiography of ameloblastoma?

Answer 15

• 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

Question 16

Histopathology of ameloblastoma?

Answer 16

• Macroscopically, ameloblastoma may show
  extensive cystic changes.
• Thickened mural areas must be sampled by
  biopsy to establish the diagnosis.
• Microscopically, many variations

Question 17

Variations of ameloblastoma?

Answer 17

Follicular and plexiform are the two main patterns.

Question 18

Can 2 forms of ameloblastoma exist n tumour?

Answer 18

Yes, can coexist

They describe the distribution of the odontogenic
epithelium within the stroma in the tumour.

Question 19

Follicular pattern of ameloblastoma?

Answer 19

• 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

Question 20

What can happen in the stellate area of ameloblastoma? (Follicular)

Answer 20

Cystic breakdown

Granular cell changes

Squamous metaplasia (acanthomatous)

Question 21

Histopathology of plexiform pattern (ameloblastoma)?

Answer 21

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.

Question 22

Behaviour of ameloblastoma?

Answer 22

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.

Question 23

Recurrent rate of ameloblastoma?

Answer 23

High recurrent - 50-90%

Question 24

Ameloblastoma malignant or locally invasive?

Answer 24

Locally invasive

Question 25

Management of ameloblastoma?

Answer 25

* 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.

Question 26

Rare variant of ameloblastoma?

Answer 26

Desmoplastic ameloblastoma

Question 27

Where is the desmoplastic amleoblasoma found?

Answer 27

Anterior mandible and maxilla

Question 28

Desmoplastic ameloblastoma?

Answer 28

* 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.

Question 29

Microscpically desmoplastic ameloblastoma?

Answer 29

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.

Question 30

Clinical presentation of uni cystic ameloblastoma?

Answer 30

* Younger age group than conventional ameloblastoma. * Posterior Mandibular (over 90% of the cases)

Question 31

Radiographing presentation of unicystic ameloblastoma?

Answer 31

* Well defined unilocular radiolucency that looks like a cyst. * Many cases are associated with an unerupted tooth, especially third molars.

Question 32

3 variants of unicystic ameloblastoma?

Answer 32

* 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.

Question 33

Recurrence of mural type unicystsic ameloblastoma?

Answer 33

High risk

Question 34

Management of unicystic ameloblastoma?

Answer 34

* 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.

Question 35

Clinical presentation of perineal ameloblastoma?

Answer 35

* 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

Question 36

Histopathology of peripheral ameloblastoma?

Answer 36

May resemble conventional ameloblastoma. * Mainly baseloid cells. * The neoplasm appears to originate from the surface epithelium. *The oral counterpart of basal cell carcinoma?

Question 37

Management of peripheral ameloblastoma?

Answer 37

* 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.

Question 38

Pathogenesis of ameloblastoma? (6)

Answer 38

* 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

Question 39

When could metastasis occur?

Answer 39

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

Question 40

New ameloblastoma?

Answer 40

Adenoid ameloblastoma