Ameloblastoma Flashcards
What is the origin of ameloblastoma
Rests of Serres
What are the rests of serres
Rests of seres are epithelial remnants in fibrous gingival tissue
What is a key component of histology in ameloblastoma
Reverse polarity of nuclei pathognomonic is a key part of ameloblastoma histology.
Name the 6 histologic subtypes;
- Follicular
- Plexiform (most common)
- Granular
- Acanthomatous
- Desmoplastic
- Basal Cell
What is the most common histologic subtype of ameloblastoma?
Plexiform
What is the histology of folicular ameloblastoma?
Palisaded ameloblastlike cells and inner zone of triangular-shaped cells resembling stellate reticulum in bell stage.
What is the common appearnce of plexiform ameloblastoma
epithelium that proliferates in a fisnhet pattern
What is the radiographic appearnce ofameloblastoma
Radiolucency with multilocularated-soap bubble appearance except for desmoplastic subtype which is radiopaque due to collagenized stroma,; root resoprtion is common
What is the clinical presenation of ameloblastoma?
Solid and/or cystic, buccolingual expansion, peripheral painless warty appearance
What is the location of ameloblastoma
Posterior mandible in desmoplastic, anterior maxilla in peripheral
What is the treatment and recurrence rate of solid or multicystic ameloblastoma?
What decade does solid or mulitcystic ameloblastoma usually occur?
4th decade
What is the treatment and recurrence rate of unicystic ameloblastoma?
What decade do unicystic subtypes typically occur?
3rd decade
What is the treatment and recurrence rate of peripheral ameloblastoma?
What decade of life does it occur?
6th decade of life, excision, with no recurrence
T/F: Ameloblastoma’s incidence exceeds that of all other odontogenic tumors
True
The tumors of course arise from the Rests of seres but also can say they arise from…
Rests of dental lamina, a developing enamel organ, the epithelial lining of an adontogenic cysts, or the basal cells of the oral mucosa
Three different variants of ameloblastoma
Which variant of ameloblastoma is most common?
Solid/multicystic which is 92% of the cases
Describe multicystic or solid ameloblastomas for me (
- About 85% occur in the posterior mandible near the ramus or mollar
- 15% occur in the posterior maxilla
- There is a painless expansion of the jaws with neursensory changes being uncommon
- Thre can be tremendous facil disfigurment.
- Most commmon radiographic feature is a multilocular radiolucency with buccal/lingual cortical expansion to the point of perforation.
- Resorption of roots is common
What is the stellate reticulum
The stellate reticulum is
- a group of cells located in the center of the enamel organ of a developing tooth.
- These cells are star-shaped and synthesize glycosaminoglycans. As glycosaminoglycans are produced, water is drawn in between the cells, stretching them apart.
- As they are moved further away from one another, the stellate reticular cells maintain contact with one another through desmosomes, resulting in their unique appearance.
- The stellate reticulum is lost after the first layer of enamel is laid down. This brings cells in the inner enamel epithelium closer to blood vessels at the periphery
Describe a picture of the stellate reticulum
Describe a diagram of the stellate reticulum.
How do the different types of multicycstic ameloblastoma (follicular and plexiform) relate to the stellate reticulum.
- Follicular in which the stellate reticulum is located within the center of the odontogenic island
- Plexiform-stellate reticulumis located outside of the odontogenic rests
What is the histological pattern of acanthomatous multicystic/solid ameloblastoma?
Squamous differentiation of the odontogenic epithelium is present
What is the histological pattern of granular cell multicystic/solid ameloblastoma?
Tumor islands exhibit cells that demonstrate abundant granular eosinophilic cytoplasm
Eosin is a bright-pink protein based dye that will therefore react or ‘stain’ proteins suspended in the cytoplasm of cells as well as extracellular proteins such as collagen. Thus, we get the term ‘eosinophilic cytoplasm’. A more inclusive term, ‘Acidophilic’, refers to all cellular tissues which react to an acid dye.
The eosinophil is a specialized cell of the immune system. This proinflammatory white blood cell generally has a nucleus with two lobes (bilobed) and cytoplasm filled with approximately 200 large granules containing enzymes and proteins with different (known and unknown) functions.
What is the histological pattern of desmoplastic multicystic/solid ameloblastoma?
Extremely dense collagenized stronga tha tsupports the tumor
What is the histological pattern of basal cell multicystic/solid ameloblastoma?
nests of uniform basaloid cells are presents with a strong resemblance to basal cell carcinoma. In this stellate reticulum is not present in the central portion o fthe nests.
What makes desmoplastic ameloblastoma unique radiographically?
It is generally not radilucent tumor due to the high content of collagenized stroma.
What pathogenetic finding is associated with the recurrence rate of ameloblastoma
Highest number of PNCA-positive cells
It aslso includes an overexpression of BCL2 and BCLX as well as the expression of IL-1 and IL-6
Multicystic/solid ameloblastomas have higher PNCA positive cells than unicystic.
T/F: There is no concensus on the biolgoic behavior of ameloblastoma
True
Why does the actual margin of ameloblastoma usually extend beyond its apparent radiographic or clinical margin?
The solid of multicystic ameloblastoma tends to infiltrate between intact cancellous bone trabeculae at the periphery of the tumor before bone resorption becomes radiographically evident so it usually extends beyond that.
Due to the agressive nature of solid/multicystic ameloblastoma, what should the resection margin be?
It should be 1.0 cm with interaoperative specimen radiographs.
Does an anatomical barrier need to be sacrificed with solid/multicystic ameloblastomas?
Yes, one uninvolved surrounding anatomic barrier should be sacrificed on the periphery of the specimen.
Is ameloblastoma malignant or benign?
Some would say malignant because it is locally invasive and prone to reoccur.
It has been compared to basal cell carcinoma which is slow growin, infiltrative, capable of greater destuction of soft tissue and bone, recurrent when not completely eradicated, capable of infading vital structures, seldom metastatic but capable of metastasis, presenting a numbe rof histological patterns
When do unicystic ameloblastomas typically form?
2nd decade, 50% happen around then and the average age is reported at 22.1
Why does unicystic ameloblastoma mimic a dentigerous cysts
Because it appears as a unilocular radiolucency is the posterior mandible
One of the histological variants of unicystic ameloblastoma is a
luminal unicystic ameloblastoma
Describe is histologiclly.
Confined to the luminal surface of the cyst. Consits of a fibrous cyst wall with a lining that consists totally or partially of ameloblastic epithelium.
One of the histological variants of unicystic ameloblastoma is a
intraluminal unicystic ameloblastoma
Describe is histologiclly.
Contains one or more nodules of ameloblastoma projecting from the cystic lining into the lumen of the cyst.
These nodules may be relatively small or largely fill the cystic lumen and are noted to show a plexiform pattern that resemles the plexiform pattern seen in conventional ameloblastomas.
These are often called plexiform unicystic ameloblastomas
One of the histological variants of unicystic ameloblastoma is a
mural ameloblastoma
Describe is histologiclly.
The fibrous wall of the cyst is infiltrated by typical follicular or plexiform ameloblastoma. The extent and depth may vary considerably
Walk me through an algorithm of a large unicystic lesion with
Luminal
Intraluminal
Mural
Treatment options
Luminal and intraluminal are usually enuclation and curretage
Mural is resection
When to resect a unicystic ameloblastoma
1-Recurrent unicystic ameloblastoma after failed enuclation and curretage
2-mural amelblastoma because it is more aggressive than luminal and intraluminal owing to the presence of the tumor in the cyst wall and its proximity to surrounding bone.
3-Management of a large tumor where enucleation and curretage would not be effective.
How do peripheral ameloblastomas present?
tumors present as non-ulcerated sessile or pedunculated gingival lesions. Most are smaller than 1.5 cm and usually occur over a wide age range.
Peripheral ameloblastomas and malignant transformation. Common or rare?
Rare
