quiz image

White Sponge Nevus

SatisfyingPlum6215 avatar
SatisfyingPlum6215
·
·
Download

Start Quiz

Study Flashcards

Questions and Answers

What is the primary cause of White Sponge Nevus?

Hereditary mutation in keratin genes

At what age are the symptoms of White Sponge Nevus typically noticed?

At birth or soon after

What is the characteristic appearance of the mucosa in White Sponge Nevus?

Thickened and folded

What is the typical location of White Sponge Nevus lesions?

<p>Multiple mucosal surfaces including buccal mucosa, tongue, and others</p> Signup and view all the answers

What is the characteristic histopathological feature of White Sponge Nevus?

<p>Marked spongiosis, acanthosis, and hyper parakeratosis</p> Signup and view all the answers

What is the treatment approach for White Sponge Nevus?

<p>No treatment necessary</p> Signup and view all the answers

What is the differential diagnosis for White Sponge Nevus?

<p>Hereditary benign epithelial dyskeratosis, Lichen planus, and others</p> Signup and view all the answers

What is the typical edge appearance of White Sponge Nevus lesions?

<p>Ill-defined</p> Signup and view all the answers

What is a characteristic feature of the histopathological examination of oral lichen planus?

<p>Liquefaction degeneration of the basal cells</p> Signup and view all the answers

Which of the following statements is true about the malignant transformation of oral lichen planus?

<p>It is more likely to occur in the plaque form of the disease</p> Signup and view all the answers

Which of the following conditions should be included in the differential diagnosis of oral lichen planus?

<p>All of the above</p> Signup and view all the answers

What is the approximate percentage of oral lichen planus cases that undergo malignant transformation over a 5-year period?

<p>0.5 to 2.5 per cent</p> Signup and view all the answers

Which of the following histopathological features is characteristic of oral lichen planus?

<p>Saw tooth configuration of the rete ridges</p> Signup and view all the answers

What is the type of lymphocytic infiltration seen in oral lichen planus?

<p>Intense band-like of lymphocytic infiltration (mainly T-lymphocyte-CD8)</p> Signup and view all the answers

Which of the following is not a characteristic feature of oral lichen planus?

<p>Hyperplasia of the basal cells</p> Signup and view all the answers

What is the name of the change seen in the epithelium-connective tissue junction in oral lichen planus?

<p>Zig-zag pattern</p> Signup and view all the answers

What is the term used to describe the superficial cell layers of the epithelium that are flattened, anucleate, and have homogeneous, eosinophilic cytoplasm?

<p>Orthokeratosis</p> Signup and view all the answers

Which of the following is an example of a preneoplastic lesion?

<p>Actinic Keratosis</p> Signup and view all the answers

What is the term used to describe the white lesions associated with the use of smokeless tobacco?

<p>Tobacco Chewer's Lesion</p> Signup and view all the answers

Which of the following is a risk factor for developing oral cancer?

<p>Actinic Keratosis</p> Signup and view all the answers

What is the term used to describe the practice of placing the lit end of a cigarette in the mouth?

<p>Reverse Smoking</p> Signup and view all the answers

Which of the following is an example of a keratotic lesion?

<p>Actinic Keratosis</p> Signup and view all the answers

What is the term used to describe the inflammation of the oral mucosa due to nicotine use?

<p>Nicotine Stomatitis</p> Signup and view all the answers

Which of the following is a diagnostic term used to describe the diagnosis of white lesions?

<p>Leukoplakia</p> Signup and view all the answers

What is the term used to describe the thickening of the keratin layer?

<p>Hyperkeratosis</p> Signup and view all the answers

What is the term used to describe the increase in the number of cells without any cytological abnormality?

<p>Hyperplasia</p> Signup and view all the answers

What is the term used to describe the thickening of the parakeratin layer?

<p>Hyperparakeratosis</p> Signup and view all the answers

What is the term used to describe a type of epithelial hyperplasia?

<p>Acanthosis</p> Signup and view all the answers

What is the term used to describe the thinning of the epithelium?

<p>Epithelial atrophy</p> Signup and view all the answers

What is the term used to describe a group of cellular changes?

<p>Cellular atypia</p> Signup and view all the answers

What is the term used to describe a bilateral, diffuse, translucent greyish, white thickening of the buccal mucosa?

<p>Leukoedema</p> Signup and view all the answers

What is the racial predilection of Leukoedema?

<p>More common in blacks</p> Signup and view all the answers

What is the term used to describe the increased thickness of one or more layers of the epithelium?

<p>Acanthosis</p> Signup and view all the answers

Which of the following is a characteristic of keratotic white lesions?

<p>Cannot be rubbed off</p> Signup and view all the answers

What is the purpose of the scrapping/wiping test using a piece of gauze?

<p>To determine whether a white patch is caused by increased keratin production or accumulation of mucosal debris</p> Signup and view all the answers

What is the classification of white lesions based on the presence or absence of epithelial dysplasia?

<p>Histological classification</p> Signup and view all the answers

Which of the following is a type of hereditary condition that causes white lesions?

<p>Leukoedema</p> Signup and view all the answers

What is the term used to describe the yellow-white appearance of oral lesions?

<p>Fibrinous exudate</p> Signup and view all the answers

What is the classification of white lesions based on the causative agents?

<p>Etiological classification</p> Signup and view all the answers

Which of the following is a characteristic of non-keratotic white lesions?

<p>Can be easily rubbed off</p> Signup and view all the answers

Half the cases are associated with the ______________ of unerupted tooth.

<p>crown</p> Signup and view all the answers

The tumor appears as a sessile ______________ on the anterior gingiva.

<p>mass</p> Signup and view all the answers

Radiographic features show an ill-defined ______________ radiolucency containing radio-opaque masses.

<p>irregular</p> Signup and view all the answers

The epithelial cells are large polyhedral with ______________ nuclei and prominent inter-cellular bridges.

<p>giant</p> Signup and view all the answers

The amyloid-like material can be stained with ______________ T and Congo red.

<p>thioflavin</p> Signup and view all the answers

The tumor is not ______________ and has a fibrovascular stroma.

<p>capsulated</p> Signup and view all the answers

Treatment involves local ______________ with a narrow margin.

<p>excision</p> Signup and view all the answers

The tumor has limited invasive potential and is therefore less ______________ than ameloblastoma.

<p>aggressive</p> Signup and view all the answers

If the lesion contains dentine, it is called Ameloblastic Fibro-_____________.

<p>dentinoma</p> Signup and view all the answers

The clinical feature of Calcifying Odontogenic Cyst is that it is most commonly found in the ______________ maxilla.

<p>anterior</p> Signup and view all the answers

Radiographically, Calcifying Odontogenic Cyst appears as a ______________ radiolucency.

<p>well-defined</p> Signup and view all the answers

Histopathologically, Calcifying Odontogenic Cyst shows a lining of odontogenic epithelium of ______________ cells in thickness.

<p>4-10</p> Signup and view all the answers

The treatment of choice for Ameloblastic Fibro-dentinoma is ______________ local excision.

<p>conservative</p> Signup and view all the answers

Calcifying Odontogenic Cyst may be associated with ______________ tooth.

<p>unerupted</p> Signup and view all the answers

Histopathologically, Calcifying Odontogenic Cyst shows a layer of ______________ cells.

<p>cuboidal or columnar</p> Signup and view all the answers

The recurrence rate of Ameloblastic Fibro-dentinoma after treatment is ______________%.

<p>20</p> Signup and view all the answers

Peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______ bearing area.

<p>tooth</p> Signup and view all the answers

The age incidence of peripheral ameloblastoma is typically in ______ patients.

<p>middle-aged</p> Signup and view all the answers

Adenomatoid odontogenic tumor is generally believed to be a ______ in nature.

<p>hamartoma</p> Signup and view all the answers

The sex incidence of adenomatoid odontogenic tumor is ______ > male.

<p>female</p> Signup and view all the answers

Adenomatoid odontogenic tumor is most commonly found in the ______ region.

<p>canine</p> Signup and view all the answers

The treatment of choice for peripheral ameloblastoma is ______ excision with a recurrence rate of 25%.

<p>surgical</p> Signup and view all the answers

The follicular type of adenomatoid odontogenic tumor is associated with the ______ of an unerupted tooth.

<p>crown</p> Signup and view all the answers

The symptom of adenomatoid odontogenic tumor is typically an ______ expansion of the bone.

<p>painless</p> Signup and view all the answers

Odontogenic fibroma is a type of ______________ tumor.

<p>benign</p> Signup and view all the answers

Ameloblastic carcinoma is a type of ______________ tumor.

<p>malignant</p> Signup and view all the answers

Clear cell odontogenic carcinoma is a type of ______________ tumor.

<p>malignant</p> Signup and view all the answers

Ameloblastoma is a type of ______________ tumor with epithelial origin.

<p>benign</p> Signup and view all the answers

Odontoma is a type of ______________ tumor with mixed origin.

<p>benign</p> Signup and view all the answers

The WHO Classification of Odontogenic Tumors was published in ______________.

<p>2017</p> Signup and view all the answers

Cementoblastoma is a type of ______________ tumor.

<p>benign</p> Signup and view all the answers

Ameloblastic fibrosarcoma is a type of ______________ tumor.

<p>malignant</p> Signup and view all the answers

The radiolucency of the follicular type of AOT extends apically along the root past the _______________ junction.

<p>cemento-enamel</p> Signup and view all the answers

The extrafollicular type of AOT is characterized by a well-defined unilocular radiolucency usually located _______________.

<p>between the roots of erupted teeth</p> Signup and view all the answers

The histopathological feature of AOT includes _______________ shaped epithelial cells that form sheets, islands, and whorled masses of cells.

<p>spindle</p> Signup and view all the answers

The duct-like structures in AOT consist of a central space surrounded by a single layer of _______________ cells.

<p>columnar</p> Signup and view all the answers

The eosinophilic material in the central space of duct-like structures is thought to be a _______________ material.

<p>basement membrane-like</p> Signup and view all the answers

The peripheral type of AOT is _______________ and accounts for about 3% of cases.

<p>rare</p> Signup and view all the answers

The follicular type of AOT involves the crown of an _______________ tooth.

<p>unerupted</p> Signup and view all the answers

The extrafollicular type of AOT may contain faint _______________ calcifications.

<p>snowflakes</p> Signup and view all the answers

Granular Cell Ameloblastoma is characterized by stellate reticulum-like cells changing to ______ cells.

<p>granular</p> Signup and view all the answers

Ameloblastic Fibroma is a rare benign mixed __________________ tumor.

<p>odontogenic</p> Signup and view all the answers

Acanthomatous Ameloblastoma is characterized by stellate reticulum-like cells undergoing ______ metaplasia.

<p>squamous</p> Signup and view all the answers

Basaloid Ameloblastoma is characterized by stellate reticulum-like cells changing to nests of ______ basaloid cells.

<p>hyperchromatic</p> Signup and view all the answers

Ameloblastic Fibroma originates from the __________________, dental follicle, or periodontal ligament.

<p>dental papilla</p> Signup and view all the answers

Desmoplastic Ameloblastoma is characterized by compressed follicles due to the deposition of a large amount of ______ fibers.

<p>collagen</p> Signup and view all the answers

The tumor is macroscopically well circumscribed and may or may not be __________________.

<p>encapsulated</p> Signup and view all the answers

The conventional ameloblastoma tends to infiltrate between intact ______ bone trabeculae at the periphery of the tumor.

<p>cancellous</p> Signup and view all the answers

The epithelial components of Ameloblastic Fibroma show one of two patterns: long anastomosing __________________ or small discrete islands resembling enamel organ.

<p>cords</p> Signup and view all the answers

The margin of the tumor often extends beyond its ______ or clinical margins.

<p>radiographic</p> Signup and view all the answers

The mesenchymal components of Ameloblastic Fibroma consist of plump stellate and ovoid cells in a loose matrix resembling the __________________ dental papilla.

<p>immature</p> Signup and view all the answers

Juxta-epithelial __________________ (cell-free zone) is seen around epithelial islands in Ameloblastic Fibroma.

<p>hyalinization</p> Signup and view all the answers

Marginal resection at least 1cm past the margins reduces the recurrence rate to ______ percent.

<p>15</p> Signup and view all the answers

Ameloblastic Fibroma is associated with an unerupted __________________.

<p>tooth</p> Signup and view all the answers

Unicystic Ameloblastoma is a locally invasive tumor that consists of a central large ______ cavity.

<p>cystic</p> Signup and view all the answers

The age incidence of Ameloblastic Fibroma is commonly seen in the 1st and 2nd __________________.

<p>decades</p> Signup and view all the answers

The odontogenic epithelium is arranged into ____________________ or islands resembling enamel organ, each follicle consists of 2 types of cells.

<p>follicles</p> Signup and view all the answers

The lesion is supported by a mature ____________________ stroma.

<p>fibrovascular</p> Signup and view all the answers

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.

<p>microcystic</p> Signup and view all the answers

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.

<p>Plexiform</p> Signup and view all the answers

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 ____________________.

<p>heamango-ameloblastoma</p> Signup and view all the answers

The supporting stroma tends to be loosely arranged & ____________________ in Plexiform Ameloblastoma.

<p>vascular</p> Signup and view all the answers

The lesion is supported by a mature ____________________ stroma in Follicular Ameloblastoma.

<p>fibrovascular</p> Signup and view all the answers

The odontogenic epithelium is arranged into follicles or islands resembling enamel organ, each follicle consists of 2 types of cells in ____________________ Ameloblastoma.

<p>Follicular</p> Signup and view all the answers

The peripheral ameloblastoma is a benign odontogenic epithelial tumor confined to the soft tissues overlying the ______________ area.

<p>tooth-bearing</p> Signup and view all the answers

The origin of peripheral ameloblastoma is from the ______________ cell layer of oral mucosa.

<p>basal</p> Signup and view all the answers

Adenomatoid odontogenic tumor is characterized by duct-like structure and variable degrees of inductive change in the ______________ stroma.

<p>CT</p> Signup and view all the answers

Adenomatoid odontogenic tumor most commonly occurs in the ______________ decade of life.

<p>2nd</p> Signup and view all the answers

Adenomatoid odontogenic tumor has a ______________ predilection in the maxilla.

<p>2:1</p> Signup and view all the answers

The treatment of choice for peripheral ameloblastoma is ______________ excision.

<p>surgical</p> Signup and view all the answers

The recurrence rate of peripheral ameloblastoma is ______________%.

<p>25</p> Signup and view all the answers

Adenomatoid odontogenic tumor is generally believed to be a ______________ in nature.

<p>hamartoma</p> Signup and view all the answers

Clinical Features of ameloblastoma include Age incidence in the ______ decade.

<p>4th-5th</p> Signup and view all the answers

Radiographic Features of ameloblastoma include ______ radiolucency.

<p>multi-locular</p> Signup and view all the answers

Conventional ameloblastoma has 2 main microscopic patterns, including ______ Ameloblastoma.

<p>Follicular</p> Signup and view all the answers

Less common histological variants of ameloblastoma include ______ Ameloblastoma.

<p>Desmoplastic</p> Signup and view all the answers

Histopathological Features of ameloblastoma include ______ Ameloblastoma.

<p>Plexiform</p> Signup and view all the answers

Less common histological variants of ameloblastoma include ______ Ameloblastoma.

<p>Basaloid</p> Signup and view all the answers

Less common histological variants of ameloblastoma include ______ Ameloblastoma.

<p>Granular Cell</p> Signup and view all the answers

Radiographic Features of ameloblastoma include ______ radiolucency, resembling cystic lesion with irregular scalloping margins.

<p>uni-locular</p> Signup and view all the answers

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

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Quizzes Like This

Fc12B epithelium 2 oct
14 questions
Alpha-Keratin Quiz
8 questions

Alpha-Keratin Quiz

AdventurousSynergy avatar
AdventurousSynergy
Clin phys 7- Skin and Hair Quiz
39 questions
Biology: Keratin and Healthy Nails
8 questions
Use Quizgecko on...
Browser
Browser