AMELOBLASTOMA – HISTOPATHOLOGY
AUTHOR: Sanketh DS, MDS
There are six different patterns of manifestation for ameloblastoma under the microscope.
This pattern is the most common type and shows several islands consisting of a central mass of cells surrounded by a peripheral layer of cells. The cells in the centre are angular to polyhedral in shape and resemble the stellate reticulum of the enamel organ.
Vicker and Gorlin’s Criteria
1. The peripheral layer of cells are tall columnar ameloblast like cells.
2. The nuclei are hyperchromatic.
Are in the opposite pole of the basement membrane – known as reversed polarity.
3. These cells show cytoplasmic vacuolization below the nucleus.
4. The central cells of these islands may often undergo cystic degeneration.
This pattern consists of long anastomosing cords or networks of odontogenic epithelium. These cords are bound by cuboidal to columnar cells surrounding the loosely arranged stellate reticulum like cells. This pattern does not strictly adhere to the Vicker and Gorlin’s criteria.
Cystic degeneration also occurs in this pattern. However degeneration happens in the connective tissue as opposed to the epithelium in the follicular pattern.
This pattern is similar to the follicular type, except that there are focal to extensive areas of squamous metaplasia (sometimes with keratin formation) in the central stellate reticulum like cells.
GRANULAR CELL PATTERN
Abundant cells with a granular eosinophilic cytoplasm replace the central cells of the odontogenic epithelial islands. These granular cells may be cuboidal,columnar or rounded.
These granules are reported to resemble lysosomes ultrastructurally.
In this pattern islands of odontogenic epithelium are less conspicuous and it consists of thin cords of epithelium in a densely fibrous stroma. It would seem like the stroma almost squeezes the epithelium thin!
Occasionally there may be irregularly shaped islands of epithelium, however, the central cells may vary from being spindle shaped to squamatoid.
BASAL CELL TYPE
Consists of nests or islands of basaloid cells and resemble basal cell carcinoma histologically! But remember, whether a tumor is diagnosed as follicular or plexiform or any other variant described, these histologic variants have no significance to prognosis or management.
Rajendran R, Sivapathasundaram B. Shafer’s Textbook of Oral Pathology. 8 th ed. Elsevier; 2016.
Neville BW, Damm DD, Allen CM, Chi A. Oral and Maxillofacial Pathology. South Asian ed. Elsevier; 2016.
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