Podcast
Questions and Answers
What is the primary cause of White Sponge Nevus?
What is the primary cause of White Sponge Nevus?
At what age are the symptoms of White Sponge Nevus typically noticed?
At what age are the symptoms of White Sponge Nevus typically noticed?
What is the characteristic appearance of the mucosa in White Sponge Nevus?
What is the characteristic appearance of the mucosa in White Sponge Nevus?
What is the typical location of White Sponge Nevus lesions?
What is the typical location of White Sponge Nevus lesions?
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What is the characteristic histopathological feature of White Sponge Nevus?
What is the characteristic histopathological feature of White Sponge Nevus?
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What is the treatment approach for White Sponge Nevus?
What is the treatment approach for White Sponge Nevus?
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What is the differential diagnosis for White Sponge Nevus?
What is the differential diagnosis for White Sponge Nevus?
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What is the typical edge appearance of White Sponge Nevus lesions?
What is the typical edge appearance of White Sponge Nevus lesions?
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What is a characteristic feature of the histopathological examination of oral lichen planus?
What is a characteristic feature of the histopathological examination of oral lichen planus?
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Which of the following statements is true about the malignant transformation of oral lichen planus?
Which of the following statements is true about the malignant transformation of oral lichen planus?
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Which of the following conditions should be included in the differential diagnosis of oral lichen planus?
Which of the following conditions should be included in the differential diagnosis of oral lichen planus?
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What is the approximate percentage of oral lichen planus cases that undergo malignant transformation over a 5-year period?
What is the approximate percentage of oral lichen planus cases that undergo malignant transformation over a 5-year period?
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Which of the following histopathological features is characteristic of oral lichen planus?
Which of the following histopathological features is characteristic of oral lichen planus?
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What is the type of lymphocytic infiltration seen in oral lichen planus?
What is the type of lymphocytic infiltration seen in oral lichen planus?
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Which of the following is not a characteristic feature of oral lichen planus?
Which of the following is not a characteristic feature of oral lichen planus?
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What is the name of the change seen in the epithelium-connective tissue junction in oral lichen planus?
What is the name of the change seen in the epithelium-connective tissue junction in oral lichen planus?
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What is the term used to describe the superficial cell layers of the epithelium that are flattened, anucleate, and have homogeneous, eosinophilic cytoplasm?
What is the term used to describe the superficial cell layers of the epithelium that are flattened, anucleate, and have homogeneous, eosinophilic cytoplasm?
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Which of the following is an example of a preneoplastic lesion?
Which of the following is an example of a preneoplastic lesion?
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What is the term used to describe the white lesions associated with the use of smokeless tobacco?
What is the term used to describe the white lesions associated with the use of smokeless tobacco?
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Which of the following is a risk factor for developing oral cancer?
Which of the following is a risk factor for developing oral cancer?
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What is the term used to describe the practice of placing the lit end of a cigarette in the mouth?
What is the term used to describe the practice of placing the lit end of a cigarette in the mouth?
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Which of the following is an example of a keratotic lesion?
Which of the following is an example of a keratotic lesion?
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What is the term used to describe the inflammation of the oral mucosa due to nicotine use?
What is the term used to describe the inflammation of the oral mucosa due to nicotine use?
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Which of the following is a diagnostic term used to describe the diagnosis of white lesions?
Which of the following is a diagnostic term used to describe the diagnosis of white lesions?
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What is the term used to describe the thickening of the keratin layer?
What is the term used to describe the thickening of the keratin layer?
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What is the term used to describe the increase in the number of cells without any cytological abnormality?
What is the term used to describe the increase in the number of cells without any cytological abnormality?
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What is the term used to describe the thickening of the parakeratin layer?
What is the term used to describe the thickening of the parakeratin layer?
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What is the term used to describe a type of epithelial hyperplasia?
What is the term used to describe a type of epithelial hyperplasia?
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What is the term used to describe the thinning of the epithelium?
What is the term used to describe the thinning of the epithelium?
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What is the term used to describe a group of cellular changes?
What is the term used to describe a group of cellular changes?
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What is the term used to describe a bilateral, diffuse, translucent greyish, white thickening of the buccal mucosa?
What is the term used to describe a bilateral, diffuse, translucent greyish, white thickening of the buccal mucosa?
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What is the racial predilection of Leukoedema?
What is the racial predilection of Leukoedema?
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What is the term used to describe the increased thickness of one or more layers of the epithelium?
What is the term used to describe the increased thickness of one or more layers of the epithelium?
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Which of the following is a characteristic of keratotic white lesions?
Which of the following is a characteristic of keratotic white lesions?
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What is the purpose of the scrapping/wiping test using a piece of gauze?
What is the purpose of the scrapping/wiping test using a piece of gauze?
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What is the classification of white lesions based on the presence or absence of epithelial dysplasia?
What is the classification of white lesions based on the presence or absence of epithelial dysplasia?
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Which of the following is a type of hereditary condition that causes white lesions?
Which of the following is a type of hereditary condition that causes white lesions?
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What is the term used to describe the yellow-white appearance of oral lesions?
What is the term used to describe the yellow-white appearance of oral lesions?
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What is the classification of white lesions based on the causative agents?
What is the classification of white lesions based on the causative agents?
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Which of the following is a characteristic of non-keratotic white lesions?
Which of the following is a characteristic of non-keratotic white lesions?
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Half the cases are associated with the ______________ of unerupted tooth.
Half the cases are associated with the ______________ of unerupted tooth.
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The tumor appears as a sessile ______________ on the anterior gingiva.
The tumor appears as a sessile ______________ on the anterior gingiva.
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Radiographic features show an ill-defined ______________ radiolucency containing radio-opaque masses.
Radiographic features show an ill-defined ______________ radiolucency containing radio-opaque masses.
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The epithelial cells are large polyhedral with ______________ nuclei and prominent inter-cellular bridges.
The epithelial cells are large polyhedral with ______________ nuclei and prominent inter-cellular bridges.
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The amyloid-like material can be stained with ______________ T and Congo red.
The amyloid-like material can be stained with ______________ T and Congo red.
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The tumor is not ______________ and has a fibrovascular stroma.
The tumor is not ______________ and has a fibrovascular stroma.
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Treatment involves local ______________ with a narrow margin.
Treatment involves local ______________ with a narrow margin.
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The tumor has limited invasive potential and is therefore less ______________ than ameloblastoma.
The tumor has limited invasive potential and is therefore less ______________ than ameloblastoma.
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If the lesion contains dentine, it is called Ameloblastic Fibro-_____________.
If the lesion contains dentine, it is called Ameloblastic Fibro-_____________.
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The clinical feature of Calcifying Odontogenic Cyst is that it is most commonly found in the ______________ maxilla.
The clinical feature of Calcifying Odontogenic Cyst is that it is most commonly found in the ______________ maxilla.
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Radiographically, Calcifying Odontogenic Cyst appears as a ______________ radiolucency.
Radiographically, Calcifying Odontogenic Cyst appears as a ______________ radiolucency.
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Histopathologically, Calcifying Odontogenic Cyst shows a lining of odontogenic epithelium of ______________ cells in thickness.
Histopathologically, Calcifying Odontogenic Cyst shows a lining of odontogenic epithelium of ______________ cells in thickness.
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The treatment of choice for Ameloblastic Fibro-dentinoma is ______________ local excision.
The treatment of choice for Ameloblastic Fibro-dentinoma is ______________ local excision.
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Calcifying Odontogenic Cyst may be associated with ______________ tooth.
Calcifying Odontogenic Cyst may be associated with ______________ tooth.
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Histopathologically, Calcifying Odontogenic Cyst shows a layer of ______________ cells.
Histopathologically, Calcifying Odontogenic Cyst shows a layer of ______________ cells.
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The recurrence rate of Ameloblastic Fibro-dentinoma after treatment is ______________%.
The recurrence rate of Ameloblastic Fibro-dentinoma after treatment is ______________%.
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Peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______ bearing area.
Peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______ bearing area.
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The age incidence of peripheral ameloblastoma is typically in ______ patients.
The age incidence of peripheral ameloblastoma is typically in ______ patients.
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Adenomatoid odontogenic tumor is generally believed to be a ______ in nature.
Adenomatoid odontogenic tumor is generally believed to be a ______ in nature.
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The sex incidence of adenomatoid odontogenic tumor is ______ > male.
The sex incidence of adenomatoid odontogenic tumor is ______ > male.
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Adenomatoid odontogenic tumor is most commonly found in the ______ region.
Adenomatoid odontogenic tumor is most commonly found in the ______ region.
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The treatment of choice for peripheral ameloblastoma is ______ excision with a recurrence rate of 25%.
The treatment of choice for peripheral ameloblastoma is ______ excision with a recurrence rate of 25%.
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The follicular type of adenomatoid odontogenic tumor is associated with the ______ of an unerupted tooth.
The follicular type of adenomatoid odontogenic tumor is associated with the ______ of an unerupted tooth.
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The symptom of adenomatoid odontogenic tumor is typically an ______ expansion of the bone.
The symptom of adenomatoid odontogenic tumor is typically an ______ expansion of the bone.
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Odontogenic fibroma is a type of ______________ tumor.
Odontogenic fibroma is a type of ______________ tumor.
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Ameloblastic carcinoma is a type of ______________ tumor.
Ameloblastic carcinoma is a type of ______________ tumor.
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Clear cell odontogenic carcinoma is a type of ______________ tumor.
Clear cell odontogenic carcinoma is a type of ______________ tumor.
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Ameloblastoma is a type of ______________ tumor with epithelial origin.
Ameloblastoma is a type of ______________ tumor with epithelial origin.
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Odontoma is a type of ______________ tumor with mixed origin.
Odontoma is a type of ______________ tumor with mixed origin.
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The WHO Classification of Odontogenic Tumors was published in ______________.
The WHO Classification of Odontogenic Tumors was published in ______________.
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Cementoblastoma is a type of ______________ tumor.
Cementoblastoma is a type of ______________ tumor.
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Ameloblastic fibrosarcoma is a type of ______________ tumor.
Ameloblastic fibrosarcoma is a type of ______________ tumor.
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The radiolucency of the follicular type of AOT extends apically along the root past the _______________ junction.
The radiolucency of the follicular type of AOT extends apically along the root past the _______________ junction.
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The extrafollicular type of AOT is characterized by a well-defined unilocular radiolucency usually located _______________.
The extrafollicular type of AOT is characterized by a well-defined unilocular radiolucency usually located _______________.
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The histopathological feature of AOT includes _______________ shaped epithelial cells that form sheets, islands, and whorled masses of cells.
The histopathological feature of AOT includes _______________ shaped epithelial cells that form sheets, islands, and whorled masses of cells.
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The duct-like structures in AOT consist of a central space surrounded by a single layer of _______________ cells.
The duct-like structures in AOT consist of a central space surrounded by a single layer of _______________ cells.
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The eosinophilic material in the central space of duct-like structures is thought to be a _______________ material.
The eosinophilic material in the central space of duct-like structures is thought to be a _______________ material.
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The peripheral type of AOT is _______________ and accounts for about 3% of cases.
The peripheral type of AOT is _______________ and accounts for about 3% of cases.
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The follicular type of AOT involves the crown of an _______________ tooth.
The follicular type of AOT involves the crown of an _______________ tooth.
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The extrafollicular type of AOT may contain faint _______________ calcifications.
The extrafollicular type of AOT may contain faint _______________ calcifications.
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Granular Cell Ameloblastoma is characterized by stellate reticulum-like cells changing to ______ cells.
Granular Cell Ameloblastoma is characterized by stellate reticulum-like cells changing to ______ cells.
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Ameloblastic Fibroma is a rare benign mixed __________________ tumor.
Ameloblastic Fibroma is a rare benign mixed __________________ tumor.
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Acanthomatous Ameloblastoma is characterized by stellate reticulum-like cells undergoing ______ metaplasia.
Acanthomatous Ameloblastoma is characterized by stellate reticulum-like cells undergoing ______ metaplasia.
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Basaloid Ameloblastoma is characterized by stellate reticulum-like cells changing to nests of ______ basaloid cells.
Basaloid Ameloblastoma is characterized by stellate reticulum-like cells changing to nests of ______ basaloid cells.
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Ameloblastic Fibroma originates from the __________________, dental follicle, or periodontal ligament.
Ameloblastic Fibroma originates from the __________________, dental follicle, or periodontal ligament.
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Desmoplastic Ameloblastoma is characterized by compressed follicles due to the deposition of a large amount of ______ fibers.
Desmoplastic Ameloblastoma is characterized by compressed follicles due to the deposition of a large amount of ______ fibers.
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The tumor is macroscopically well circumscribed and may or may not be __________________.
The tumor is macroscopically well circumscribed and may or may not be __________________.
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The conventional ameloblastoma tends to infiltrate between intact ______ bone trabeculae at the periphery of the tumor.
The conventional ameloblastoma tends to infiltrate between intact ______ bone trabeculae at the periphery of the tumor.
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The epithelial components of Ameloblastic Fibroma show one of two patterns: long anastomosing __________________ or small discrete islands resembling enamel organ.
The epithelial components of Ameloblastic Fibroma show one of two patterns: long anastomosing __________________ or small discrete islands resembling enamel organ.
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The margin of the tumor often extends beyond its ______ or clinical margins.
The margin of the tumor often extends beyond its ______ or clinical margins.
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The mesenchymal components of Ameloblastic Fibroma consist of plump stellate and ovoid cells in a loose matrix resembling the __________________ dental papilla.
The mesenchymal components of Ameloblastic Fibroma consist of plump stellate and ovoid cells in a loose matrix resembling the __________________ dental papilla.
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Juxta-epithelial __________________ (cell-free zone) is seen around epithelial islands in Ameloblastic Fibroma.
Juxta-epithelial __________________ (cell-free zone) is seen around epithelial islands in Ameloblastic Fibroma.
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Marginal resection at least 1cm past the margins reduces the recurrence rate to ______ percent.
Marginal resection at least 1cm past the margins reduces the recurrence rate to ______ percent.
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Ameloblastic Fibroma is associated with an unerupted __________________.
Ameloblastic Fibroma is associated with an unerupted __________________.
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Unicystic Ameloblastoma is a locally invasive tumor that consists of a central large ______ cavity.
Unicystic Ameloblastoma is a locally invasive tumor that consists of a central large ______ cavity.
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The age incidence of Ameloblastic Fibroma is commonly seen in the 1st and 2nd __________________.
The age incidence of Ameloblastic Fibroma is commonly seen in the 1st and 2nd __________________.
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The odontogenic epithelium is arranged into ____________________ or islands resembling enamel organ, each follicle consists of 2 types of cells.
The odontogenic epithelium is arranged into ____________________ or islands resembling enamel organ, each follicle consists of 2 types of cells.
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The lesion is supported by a mature ____________________ stroma.
The lesion is supported by a mature ____________________ stroma.
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Central cystic formation is common due to degeneration in central cells within the follicle resulting in ____________________ spaces & macrocystic spaces with flattening of ameloblast-like cells.
Central cystic formation is common due to degeneration in central cells within the follicle resulting in ____________________ spaces & macrocystic spaces with flattening of ameloblast-like cells.
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The odontogenic epithelium is arranged in a network of anastomosing strands & cords with the same layers as follicular ameloblastoma (ameloblast-like cells & stellate reticulum-like cells) in ____________________ Ameloblastoma.
The odontogenic epithelium is arranged in a network of anastomosing strands & cords with the same layers as follicular ameloblastoma (ameloblast-like cells & stellate reticulum-like cells) in ____________________ Ameloblastoma.
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Cystic formation is due to degeneration in C.T.stroma rather than cystic change within the epithelium as follicular pattern, then, dilated blood vessels are left without any support.They become enlarged & rupture leading to escape of blood into stromal spaces.These cases are known as ____________________.
Cystic formation is due to degeneration in C.T.stroma rather than cystic change within the epithelium as follicular pattern, then, dilated blood vessels are left without any support.They become enlarged & rupture leading to escape of blood into stromal spaces.These cases are known as ____________________.
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The supporting stroma tends to be loosely arranged & ____________________ in Plexiform Ameloblastoma.
The supporting stroma tends to be loosely arranged & ____________________ in Plexiform Ameloblastoma.
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The lesion is supported by a mature ____________________ stroma in Follicular Ameloblastoma.
The lesion is supported by a mature ____________________ stroma in Follicular Ameloblastoma.
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The odontogenic epithelium is arranged into follicles or islands resembling enamel organ, each follicle consists of 2 types of cells in ____________________ Ameloblastoma.
The odontogenic epithelium is arranged into follicles or islands resembling enamel organ, each follicle consists of 2 types of cells in ____________________ Ameloblastoma.
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The peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______________ area.
The peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______________ area.
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The origin of peripheral ameloblastoma is from the ______________ cell layer of oral mucosa.
The origin of peripheral ameloblastoma is from the ______________ cell layer of oral mucosa.
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Adenomatoid odontogenic tumor is characterized by duct-like structure and variable degrees of inductive change in the ______________ stroma.
Adenomatoid odontogenic tumor is characterized by duct-like structure and variable degrees of inductive change in the ______________ stroma.
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Adenomatoid odontogenic tumor most commonly occurs in the ______________ decade of life.
Adenomatoid odontogenic tumor most commonly occurs in the ______________ decade of life.
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Adenomatoid odontogenic tumor has a ______________ predilection in the maxilla.
Adenomatoid odontogenic tumor has a ______________ predilection in the maxilla.
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The treatment of choice for peripheral ameloblastoma is ______________ excision.
The treatment of choice for peripheral ameloblastoma is ______________ excision.
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The recurrence rate of peripheral ameloblastoma is ______________%.
The recurrence rate of peripheral ameloblastoma is ______________%.
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Adenomatoid odontogenic tumor is generally believed to be a ______________ in nature.
Adenomatoid odontogenic tumor is generally believed to be a ______________ in nature.
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Clinical Features of ameloblastoma include Age incidence in the ______ decade.
Clinical Features of ameloblastoma include Age incidence in the ______ decade.
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Radiographic Features of ameloblastoma include ______ radiolucency.
Radiographic Features of ameloblastoma include ______ radiolucency.
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Conventional ameloblastoma has 2 main microscopic patterns, including ______ Ameloblastoma.
Conventional ameloblastoma has 2 main microscopic patterns, including ______ Ameloblastoma.
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Less common histological variants of ameloblastoma include ______ Ameloblastoma.
Less common histological variants of ameloblastoma include ______ Ameloblastoma.
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Histopathological Features of ameloblastoma include ______ Ameloblastoma.
Histopathological Features of ameloblastoma include ______ Ameloblastoma.
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Less common histological variants of ameloblastoma include ______ Ameloblastoma.
Less common histological variants of ameloblastoma include ______ Ameloblastoma.
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Less common histological variants of ameloblastoma include ______ Ameloblastoma.
Less common histological variants of ameloblastoma include ______ Ameloblastoma.
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Radiographic Features of ameloblastoma include ______ radiolucency, resembling cystic lesion with irregular scalloping margins.
Radiographic Features of ameloblastoma include ______ radiolucency, resembling cystic lesion with irregular scalloping margins.
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Study Notes
White Sponge Nevus (WSN)
- Caused by point mutation in keratin genes leading to irregular keratin production on the mucosal surface
- Clinical features:
- Noticed at birth or soon after and increases with age
- Affects any part of the oral mucosa, as well as other mucosal surfaces in the body (extra-orally)
- Oral lesions are bilateral, symmetric, and usually appear before puberty
- Mucosa appears thickened and folded or corrugated with a soft or spongy texture and white hue
- Lesions are almost asymptomatic and have ill-defined edges
- Histopathological features:
- Epithelium is greatly thickened with marked spongiosis, acanthosis, and hyperparakeratosis
- Within the stratum spinosum, marked hydroptic change with intracellular edema and abnormally prominent epithelial cell membranes
- Pathognomic perinuclear eosinophilic condensation of cytoplasm characteristic of prickle cells in WSN
Oral Lichen Planus (OLP)
- Clinical features:
- Bilateral and symmetric lesions
- Affects any part of the oral mucosa
- Mucosa appears thickened and folded or corrugated with a soft or spongy texture and white hue
- Lesions are almost asymptomatic and have ill-defined edges
- Histopathological features:
- Varying degrees of hyperorthokeratosis or hyperparakeratosis of epithelium surface
- Thickening of the granular cell layer
- Acanthosis of the spinous layer
- Liquefaction degeneration of the basal cells
- Apoptotic (degenerated) basal keratinocytes may be seen
- Intense band-like of lymphocytic infiltration (mainly T-lymphocyte-CD8) immediately subjacent to the epithelium
- Malignant transformation:
- Almost all cases of oral lichen planus run a benign course, but malignant transformation has been described in a very small proportion
- Some studies have suggested that the atrophic/erosive forms are more likely to undergo such change
- It ranges from about 0.5 to 2.5 per cent over a 5-year period
Classification of Oral White Lesions
- Clinical classification:
- Normal oral mucosa with variation in structure and appearance
- Nonkeratotic white lesion (Non-epithelial white lesion)
- Keratotic white lesions
- Histological classification:
- Those show epithelial dysplasia
- Those that don’t show it
- Etiological classification:
- Hereditary conditions (Hereditary Keratosis)
- Reactive/Inflammatory lesions
- Preneoplastic (Premalignant) & Neoplastic lesions
- Dermatosis (immunological) diseases
- Infectious
- Non-epithelial white lesions
- White benign lesions caused by human papilloma virus (HPV)
Odontogenic Tumors
- Odontogenic tumors are classified into two categories: benign and malignant
- Benign odontogenic tumors include:
- Ameloblastoma
- Ameloblastoma, unicystic type
- Ameloblastoma, extraosseous/peripheral type
- Metastasizing (malignant) ameloblastoma
- Squamous odontogenic tumor
- Calcifying epithelial odontogenic tumor
- Adenomatoid odontogenic tumor
- Mixed (epithelial-mesenchymal) origin tumors include:
- Ameloblastic fibroma
- Primordial odontogenic tumor
- Odontoma, complex type
- Odontoma, compound type
- Dentinogenic ghost cell tumor
Calcifying Odontogenic Cyst (COC)
- Definition: a benign mixed odontogenic cystic lesion
- Age incidence: 2nd and 3rd decades
- Site predilection: most commonly anterior maxilla (canine region)
- May be associated with odontomas
- Radiographic features:
- Well-defined unilocular or multilocular radiolucency
- Contain radio-opaque masses
- Histopathological features:
- Well-defined cystic lesion with a fibrous capsule
- Lining of odontogenic epithelium of 4-10 cells in thickness
- Basal layer of cuboidal or columnar cells (ameloblast-like cells)
- Overlying layer of loosely arranged cells (stellate reticulum-like cells)
Peripheral (Extraosseous) Ameloblastoma
- Definition: a benign odontogenic epithelial tumor confined to the soft tissues overlying the tooth-bearing area
- Age incidence: middle-aged patients
- Site predilection: posterior gingival and alveolar mucosa
- Mandible > maxilla
- Symptom & signs: painless non-ulcerated sessile or pedunculated gingival or alveolar mucosal lesion
- Histopathological feature: as conventional pattern
- Treatment: surgical excision is treatment of choice with a recurrence rate of 25%
Adenomatoid Odontogenic Tumor (AOT)
- Definition: a benign epithelial odontogenic tumor, characterized by duct-like structure and variable degrees of inductive change in C.T. stroma
- Origin: enamel organ epithelium and remnants of dental lamina
- Clinical features:
- Age incidence: 2nd decade of life
- Sex incidence: female > male
- Site predilection: maxilla > mandible (2:1)
- Most common in canine region
- Symptom & signs: asymptomatic, slowly growing small lesion, painless expansion of the bone
- AOT Variants:
- Central (intraosseous): associated with the crown of an unerupted tooth
- Peripheral (extraosseous): rare, situated in gingiva
Malignant Odontogenic Tumors
- Odontogenic Carcinomas:
- Metastasizing (malignant) ameloblastoma
- Ameloblastic carcinoma – primary type
- Ameloblastic carcinoma – secondary type, intraosseous
- Ameloblastic carcinoma – secondary type, peripheral
- Primary intraosseous squamous cell carcinoma – solid type
- Primary intraosseous squamous carcinoma derived from keratocystic odontogenic tumor
- Primary intraosseous squamous cell carcinoma derived from odontogenic cysts
- Clear cell odontogenic carcinoma
- Ghost cell odontogenic carcinoma
- Odontogenic Sarcomas:
- Ameloblastic fibrosarcoma
- Ameloblastic fibro-dentino and fibro-odontosarcoma
Granular Cell Ameloblastoma
- Characterized by stellate reticulum-like cells changing to granular cells, which may be cuboidal or rounded in shape with their nuclei pushed to the cell wall
- Cytoplasm filled with eosinophilic granules, which represent lysosomes as shown by electron microscopic study
Acanthomatous Ameloblastoma
- Stellate reticulum-like cells undergo squamous metaplasia, producing keratin in the form of keratin pearls
- May be confused with squamous cell carcinoma or squamous odontogenic tumor
Basaloid Ameloblastoma
- Stellate reticulum-like cells change to nests of hyperchromatic basaloid cells
- Shows close similarity to basal cell carcinoma
Desmoplastic Ameloblastoma
- Characterized by compressed follicles due to deposition of a large amount of collagen fibers in the CT stroma, leading to a bizarre-like shape
- Hyalinized CT stroma: the stroma undergoes hyalinization to involve a zone of about 30 microns immediately adjacent to the epithelial follicle, which is due to hyaline degeneration of collagen fibers and never calcifies, remaining eosinophilic
Treatment of Ameloblastoma
- Conventional ameloblastoma tends to infiltrate between intact cancellous bone trabeculae at the periphery of the tumor
- The margin of the tumor often extends beyond its radiographic or clinical margins, therefore, with curettage, the recurrence rate is 50% to 90%
- Marginal resection at least 1cm past the margins reduces the recurrence rate to 15%
Unicystic Ameloblastoma
- Definition: Locally invasive tumor consisting of a central large cystic cavity, which is less aggressive than conventional ameloblastoma
- Origin: De-novo as a neoplasm
Ameloblastic Fibroma
- Definition: Rare benign mixed odontogenic tumor in which both the epithelium and ectomesenchymal tissues are neoplastic
- Origin: Dental papilla, dental follicle, or periodontal ligament
- Clinical Features:
- Age incidence: 1st and 2nd decades
- Sex incidence: Male > Female
- Site predilection: Mandibular premolar-molar area
- Symptom & signs: Painless, slowly growing swelling
- Radiographic Features:
- Well-defined unilocular (mainly) or multilocular radiolucent area
- May be surrounded by a sclerotic border
- Often associated with an unerupted tooth
- Histopathological Features:
- The tumor is macroscopically well-circumscribed and may or may not be encapsulated
- Highly cellular mesenchymal tissue resembling the primitive dental papilla, mixed with proliferated odontogenic epithelium
- The epithelial components:
- Show one of two patterns: Long anastomosing cords, strands, or small discrete islands resembling enamel organ
- Composed of cuboidal or columnar cells
- The mesenchymal components:
- Consist of plump stellate and ovoid cells in a loose matrix resembling the immature dental papilla with little collagen fibers
- Juxta-epithelial hyalinization (cell-free zone) around epithelial islands
Clinical Features of Ameloblastoma
- Age incidence: 4th-5th decade
- Sex incidence: Male = Female
- Race incidence: ↑↑ in African
- Site predilection:
- Mandible > Maxilla
- In mandible, 70% in molar-ramus area, 20% in premolar area, and 10% in incisor region
- Signs & Symptoms:
- Slowly growing bony swelling with locally invasive behavior
- In early stages, may be asymptomatic and discovered during routine x-ray
- Later, it may produce gradual facial asymmetry and thinning of the cortical bone, resulting in an egg-shell crackling
- Pain & paresthesia may occur if the lesion is pressing upon a nerve or secondarily infected
- Displacement & looseness of involved teeth
- If left untreated for many years, carcinoma can be seen
Radiographic Features of Ameloblastoma
- Multi-locular radiolucency:
- Soap bubble: when loculations are large
- Honey combed: when loculations are small
- Uni-locular radiolucency; resembling a cystic lesion with irregular scalloping margins
- Root resorption & tooth displacement
- May be associated with an un-erupted tooth, especially the lower wisdom
Histopathological Features of Ameloblastoma
- Conventional ameloblastoma has 2 main microscopic patterns (depending on the arrangement of epithelium):
- Follicular Ameloblastoma
- Plexiform Ameloblastoma
- In some tumors, both patterns coexist with no difference in the clinical behavior between various types
- Less common histological variants of ameloblastoma include:
- Acanthomatous Ameloblastoma
- Granular Cell Ameloblastoma
- Basaloid Ameloblastoma
- Desmoplastic Ameloblastoma
Follicular Ameloblastoma
- The most common pattern
- The odontogenic epithelium is arranged into follicles or islands resembling enamel organ, each follicle consists of 2 types of cells:
- Peripheral single layer of tall columnar cells with reversed polarity
- Central core of loosely arranged angular or star-shaped cells
- The lesion is supported by a mature fibrovascular CT stroma
- Central cystic formation is common due to degeneration in central cells within the follicle, resulting in microcystic spaces and macrocystic spaces with flattening of ameloblast-like cells
Plexiform Ameloblastoma
- The odontogenic epithelium is arranged in a network of anastomosing strands and cords with the same layers as follicular ameloblastoma
- The supporting stroma tends to be loosely arranged and vascular
- Cystic formation is due to degeneration in CT stroma rather than cystic change within the epithelium as in the follicular pattern
- Then, dilated blood vessels are left without any support, they become enlarged and rupture, leading to escape of blood into stromal spaces, known as hemango-ameloblastoma
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Description
A genetic disorder characterized by mutations in keratin genes, leading to abnormal keratin production on mucosal surfaces. It affects the oral mucosa and other mucosal surfaces, causing bilateral and symmetric lesions.
