a review of ameloblastoma

A REVIEW OF A REVIEW OF AMELOBLASTOMAAMELOBLASTOMA

ByByJolayemi Judith O.MJolayemi Judith O.M

600l bds600l bdsCODEH chairmanCODEH chairman

Coll of med. Univ. of lagos Coll of med. Univ. of lagos

OutlineOutline

IntroductionIntroductionAetiopathogenesisAetiopathogenesisClinical featuresClinical featuresHistopathologyHistopathologyRadiographic featuresRadiographic featuresTreatment/prognosisTreatment/prognosisDifferential diagnosisDifferential diagnosisCase presentationCase presentation

IntroductionIntroduction

Ameloblastoma is a benign, slow growing tumor Ameloblastoma is a benign, slow growing tumor of odontogenic origin, composed of epithelial of odontogenic origin, composed of epithelial cells that resemble enamel-producing cells but cells that resemble enamel-producing cells but do not form enamel. While this tumors are rarely do not form enamel. While this tumors are rarely malignant or metastatic, and progress slowly, malignant or metastatic, and progress slowly, the resulting lesions can cause severe the resulting lesions can cause severe abnormalities of the face and jaw. The abnormal abnormalities of the face and jaw. The abnormal cell growth easily infiltrates and destroys cell growth easily infiltrates and destroys surrounding bony tissues. It is therefore surrounding bony tissues. It is therefore appreciated for its locally aggressive behavior. appreciated for its locally aggressive behavior.

AetiopathogenesisAetiopathogenesis

The neoplasm originates within the mandible or The neoplasm originates within the mandible or maxilla from tooth-forming epithelium. Potential maxilla from tooth-forming epithelium. Potential epithelial sources include enamel organ, epithelial sources include enamel organ, odontogenic rests (rest cells of Malassez, rests odontogenic rests (rest cells of Malassez, rests of Serres), reduced enamel epithelium, epithelial of Serres), reduced enamel epithelium, epithelial lining of odontogenic cysts esp. the dentigerous lining of odontogenic cysts esp. the dentigerous cysts. The trigger or stimulus for neoplastic cysts. The trigger or stimulus for neoplastic transformation of these epitheliaal structures is transformation of these epitheliaal structures is however unknown.however unknown.

Clinical featuresClinical features

Ameloblastoma is predominant in adults in the 4Ameloblastoma is predominant in adults in the 4thth and 5 and 5thth decades of life with the mean age being 35-45 years. It decades of life with the mean age being 35-45 years. It rarely occurs in children (unicystic type) they may occur rarely occurs in children (unicystic type) they may occur anywhere in the jaws, although the mandibular molar-anywhere in the jaws, although the mandibular molar-ramus area is the most favored site. It is usually ramus area is the most favored site. It is usually asymptomatic, unless complicated by secondary asymptomatic, unless complicated by secondary infection, and are discovered during routine examination, infection, and are discovered during routine examination, or because of asymptomatic jaw expansion. It causes or because of asymptomatic jaw expansion. It causes buccal and lingual expansion of bone. Occasional tooth buccal and lingual expansion of bone. Occasional tooth movement or malocclusion may be the initial presenting movement or malocclusion may be the initial presenting sign. sign.

Clinical featuresClinical features

HistopathologyHistopathology

Numerous histological patterns have been described. Numerous histological patterns have been described. Some may exhibit a single histologic subtype, others Some may exhibit a single histologic subtype, others may show several patterns in the same lesion. Common may show several patterns in the same lesion. Common to nearly all subtypes is the polarization of cells around to nearly all subtypes is the polarization of cells around the proliferating nests in a pattern similar to ameloblasts the proliferating nests in a pattern similar to ameloblasts of the enamel organ. Central to these cells are loosely of the enamel organ. Central to these cells are loosely arranged stellate reticulum-like cells. Another typical arranged stellate reticulum-like cells. Another typical feature is the budding of the tumor cells from neoplastic feature is the budding of the tumor cells from neoplastic foci in a pattern reminiscent of tooth development. foci in a pattern reminiscent of tooth development.

Histopathology cont’dHistopathology cont’d

Follicular typeFollicular type-- the microscopic subtype most the microscopic subtype most commonly seen. It is composed of islands of commonly seen. It is composed of islands of tumor cells that mimic the dental follicle. The tumor cells that mimic the dental follicle. The ameloblast-like cells are tall columnar with their ameloblast-like cells are tall columnar with their nuclei palisaded to the opposite pole of the nuclei palisaded to the opposite pole of the basement membrane.basement membrane.


Plexiform typePlexiform type-- thin trabeculae of thin trabeculae of epithelial cells in connective tissue stroma. epithelial cells in connective tissue stroma.


Acanthomatous typeAcanthomatous type-- squamous squamous metaplasia of central core epithelium metaplasia of central core epithelium though, it resembles the follicular type.though, it resembles the follicular type.

Basal cell typeBasal cell type-- rare, there are small rare, there are small darkly staining cells in a trabeculae darkly staining cells in a trabeculae pattern, but with little palisading at the pattern, but with little palisading at the periphery. Can be mistaken for basal cell periphery. Can be mistaken for basal cell carcinomas. carcinomas.


Granular cell typeGranular cell type-- rare, usually resembles the rare, usually resembles the follicular type but tumor islands contain large follicular type but tumor islands contain large eosinophilic granular epithelial cells. eosinophilic granular epithelial cells.

Desmoplastic typeDesmoplastic type- - cells are not standard in cells are not standard in appearance. Connective tissue is densely appearance. Connective tissue is densely collagenised collagenised

Clear cell typeClear cell type- - more aggressive.more aggressive. Peripheral ameloblastomaPeripheral ameloblastoma-- occurs in soft tissue. occurs in soft tissue.


Ameloblastomas have been subdivided Ameloblastomas have been subdivided into two subtypes based on their biology into two subtypes based on their biology and microscopy- and microscopy-

1.1. Solid or multilocular[ more aggressive Solid or multilocular[ more aggressive and will require more extensive and will require more extensive treatment. It also has a high recurrence treatment. It also has a high recurrence rate]rate]

2.2. Cystic or unicysticCystic or unicystic

Radiographic featuresRadiographic features

Radiographically, ameloblastomas appear Radiographically, ameloblastomas appear as osteolytic processes. The tumors as osteolytic processes. The tumors typically found in the tooth-bearing areas typically found in the tooth-bearing areas of the jaws may be unilocular or of the jaws may be unilocular or multilocular . It often gives a soap- bubble multilocular . It often gives a soap- bubble appearance. Margins are usually well-appearance. Margins are usually well-defined and sclerotic. Radiographic extent defined and sclerotic. Radiographic extent may be deceptive.may be deceptive.

Treatment/prognosis

There is no single standard type of therapy, rather each There is no single standard type of therapy, rather each case should be judged on its own merits. Treatment case should be judged on its own merits. Treatment ranges from surgical excision with about 2cm margin of ranges from surgical excision with about 2cm margin of safety(solid multicystic type), block excision or resection safety(solid multicystic type), block excision or resection for larger lesions, or enucleation for smaller ones. It is for larger lesions, or enucleation for smaller ones. It is believed that the lesion is radioresistant, however, believed that the lesion is radioresistant, however, evidence shows that radiation may produce significant evidence shows that radiation may produce significant therapeutic results. Radiation is restricted to cases therapeutic results. Radiation is restricted to cases where surgery may be unacceptably destructive, where surgery may be unacceptably destructive, primarily maxillary lesions. primarily maxillary lesions.

Treatment/prognosis cont’dTreatment/prognosis cont’d

Malignant types of ameloblastomas are Malignant types of ameloblastomas are rare. They occur in the younger age and rare. They occur in the younger age and appear more in the mandible. They appear more in the mandible. They metastasize to lymph nodes or distant metastasize to lymph nodes or distant organs. There are two subtypes of organs. There are two subtypes of malignant ameloblastomas: malignant ameloblastomas:

1.1. Malignant ameloblastomaMalignant ameloblastoma

2.2. Ameloblastsic carcinomaAmeloblastsic carcinoma

Treatment/prognosis cont’dTreatment/prognosis cont’d

Metastasis from malignant Metastasis from malignant ameloblastomas appear usually in the ameloblastomas appear usually in the lung{probably due to aspiration of tumor lung{probably due to aspiration of tumor cells}. Second most affected site is the cells}. Second most affected site is the lymph nodes, followed by the skull, liver, lymph nodes, followed by the skull, liver, spleen, kidney and skin. spleen, kidney and skin.

Differential diagnosisDifferential diagnosis

CEOTCEOTDentigerous cystDentigerous cystOKCystOKCystCentral giant cell granulomaCentral giant cell granulomaOssifying fibromaOssifying fibroma

.. ..

Case presentationCase presentation

A 40 year old man presented with a swelling in A 40 year old man presented with a swelling in the left side of the mandible of about 3 years the left side of the mandible of about 3 years duration. The lesion spans the lower left 5-7. It is duration. The lesion spans the lower left 5-7. It is painless. On examination, there was bucolingual painless. On examination, there was bucolingual expansion of the affected area, mobility of the expansion of the affected area, mobility of the lower left 4,5,6&7. Radiograph revealed lower left 4,5,6&7. Radiograph revealed multilobulated areas giving a soap bubble multilobulated areas giving a soap bubble appearance. Histology showed peripheral cells appearance. Histology showed peripheral cells resembling ameloblasts and central cells resembling ameloblasts and central cells resembling stellate reticulum cells. Give a resembling stellate reticulum cells. Give a probable diagnosis and differentials.probable diagnosis and differentials.

thankthank

youyou

a review of ameloblastoma

Documents

follicular

histopathology

lymph nodes

tumor cells

epithelial

malignant

tooth

aggressive