Odontogenic Tumors
Classification of Odontogenic TumorsI. Tumors of odontogenic epithelium A. Ameloblastoma 1. Malignant ameloblastoma 2. Ameloblastic carcinoma B. Clear cell odontogenic carcinoma C. Adenomatoid odontogenic tumor D. Calcifying epithelial odontogenic tumor E. Squamous odontogenic tumor II. Mixed odontogenic tumors A. Ameloblastic fibroma B. Ameloblastic fibro-odontoma C. Ameloblastic fibrosarcoma D. Odontoameloblastoma E. Compound odontoma F. Complex odontoma III. Tumors of odontogenic mesenchyme A. Odontogenic fibroma B. Granular cell odontogenic tumor C. Odontogenic myxoma D. Cementoblastoma
Tumors of Odontogenic Epithelium
AmeloblastomaThe ameloblastoma is common odontogenic tumor. It may develop from cell rests of the enamel organ; from the developing enamel organ; from the lining of odontogenic cysts or from the basal cells of the oral mucosa. It is typically slow-growing, locally invasive and runs a benign course.
Ameloblastoma
Ameloblastomas occur in 3 different clinico-radiographic situations requiring different therapeutic considerations and having different prognosis. Conventional Solid/Multicystic (86 % of all cases) Unicystic (13 % of all cases) Peripheral or Extraosseous (1 % of all cases)Solid or Multicystic Ameloblastoma: Clinical Features
Patient Age: Approximately equal frequency from the third through the seventh decades. Sex Predilection: Approximately equal. Location: 80 % in mandible; 70 % in posterior regions. Radiographic Appearance: Radiolucent lesion which is usually well-circumscribed; it is multilocular (soap-bubble, honeycomb). While lesions are generally asymptomatic, ameloblastomas may cause paresthesia, pain particularly if infected and they can erode the cortical palates.Solid or Multicystic Ameloblastoma: Histologic Features
There are several microscopic subtypes but these generally have little bearing on the behavior of the tumor. The follicular and plexiform types are the most common. The follicular type is composed of islands of epithelium which resemble the enamel organ in a mature fibrous connective tissue stoma.
Solid or Multicystic Ameloblastoma: Histologic Features
The plexiform type is composed of long, anastomosing cords of odontogenic epithelium. Its stroma tends to be loose and more vascular. The acanthomatous type shows evidence of extensive squamous metaplasia with keratin formation in the island of odontogenic epithelium.Solid or Multicystic Ameloblastoma: Histologic Features
In the granular cell type there is transformation of groups of epithelial cells to granular cells; the nature of the granular change is unknown. This type is more common in young patients and has been shown to be clinically aggressive.Solid or Multicystic Ameloblastoma: Histologic Features
The desmoplastic form is composed of islands/cords of odontogenic epithelium in a very dense collagenous stroma. It has a predilection for the anterior maxilla and because of the dense connective tissue may appear as a radiolucent-radiopaque lesion. The basaloid type is the least common and is composed of uniform basaloid cells with no stellate reticulum.Unicystic Ameloblastoma: Clinical Features
Patient Age: The patients are younger than those with the solid/multicystic form. 50% are diagnosed during the second decade of life. Radiographic Appearance: Typically appears as a radiolucency around the crown of an unerupted tooth (most commonly a mandibular third molar).Unicystic Ameloblastoma: Histologic Features
Three histopathologic variants are recognized: Luminal: the tumor is confined to the luminal surface of the cyst. Intraluminal: the tumor projects from the cystic lining. Mural: the tumor infiltrates the fibrous cystic wall.Three histopathologic variants:
Peripheral AmeloblastomaThese tumors are extraosseous and therefore occupy the lamina propria underneath the surface epithelium but outside of the bone. Radiographic Appearance: Although not in bone, a few cases have shown superficial erosion of the alveolar bone. There is a slight predilection for the mandible. The buccal mucosa has been the site in a few reported cases. Histologically, these lesions have the same features as the intraosseous forms of the tumor. Patients respond well to local surgical excision, and some reports indicate a 25 % recurrence rate
Malignant Ameloblastoma and Ameloblastic Carcinoma
Less than 1 % of the ameloblastomas show malignant behavior with the development of metastases.Malignant Ameloblastoma & Ameloblastic Carcinoma: Clinical
Patients range in age from 4-75 with a mean of 30 years. Metastases most often occur in the lungs. Spread has also occurred to the cervical lymph nodes and to vertebrae and viscera.Malignant Ameloblastoma & Ameloblastic Carcinoma: X-Ray
With the malignant ameloblastoma, the appearance is similar to the typical solid/multicystic ameloblastoma. The ameloblastic carcinoma is often more aggressive with the lesion appearing as an ill-defined radiolucency with cortical destruction.Malignant Ameloblastoma & Ameloblastic Carcinoma: Histology
With the malignant ameloblastoma, both the primary and metastases show no microscopic features that differ from those of the typical solid/multicystic ameloblastoma. The ameloblastic carcinoma shows cytological features of malignancy in addition to a pattern of an ameloblastoma.Ameloblastic Carcinoma
Adenomatoid Odontogenic Tumor (AOT)AOT represents about 3-7 % of all odontogenic tumors.
AOT: Clinical Features
Patient Age: The peak age is in the second decade with a mean around 17 years. Gender Predilection: Females, 2:1. Location: Sixty-five percent of the AOTs occur in the maxilla with 65 % occurring in the canine region. Seventy-five percent of the cases are associated with the crown of an unerupted tooth. On rare occasion the lesion is extraosseous.AOT: Radiographic and Additional Features
AOTs typically appear as pericoronal radiolucencies, which may have radiopaque material within the lucency.These lesions are frequently asymptomatic and therefore are discovered upon routine radiographic examination. AOTs may also block the eruption of a permanent tooth and be discovered when radiographs are taken to “search for” the unerupted tooth.AOT: Histologic Features
The lesion is usually surrounded by a thick, fibrous capsule. The tumor is composed of spindle-shaped epithelial cells that form sheets, strands or whorled masses with little connective tissue. The epithelial cells may form rosette-like structures, tubular or duct-like structures may be prominent or absent. Calcifications may be observed in the tumor mass.AOT: Treatment and Prognosis
Enucleation is the treatment of choice as the tumor is easily removed from the bone. AOTs seldom recur.Adenomatoid tumor
Calcifying Epithelial Odontogenic Tumor (CEOT; Pindborg Tumor)Pindborg tumor accounts for < 1 % of all odontogenic tumors.
CEOT: Clinical Features
Patient Age: Patients ages range from the second to the tenth decades with a mean around 40 years. Gender Predilection: There is no reported sex predilection. Location: 75 % of the CEOTs occur in the mandible with most occurring in the posterior region. A rare peripheral CEOT does occur. Bony lesions most commonly present as painless, slow-growing swellings.CEOT: Radiographic Features
CEOTs occur as radiolucent lesions with/without opaque foci. They are usually well-circumscribed and may be unilocular or multilocular. Slightly over 50 % of the CEOTs are associated with an unerupted tooth.CEOT: Histologic Features
This lesion is typically composed of islands, sheets or strands of polyhedral epithelial cells in a fibrous stroma. Cells outlines are distinct and intercellular bridges may be seen. Nuclei show considerable variation with giant nuclei and pleomorphism observed. Calcifications may be noted as well as amyloid-like material.CEOT: Additional Features, Treatment and Prognosis
Conservative local resection is the treatment of choice as these lesions are typically less aggressive than the ameloblastoma. With this treatment the recurrence rate is approximately 15 % and the overall prognosis is good.Mixed Odontogenic Tumors
Ameloblastic Fibroma: Clinical Features
This true mixed odontogenic tumor is more common in patients in the first and second decades of life with a mean of 14 years. It is slightly more common in males than females. Approximately 70 % of the ameloblastic fibromas occur in the posterior mandible. Small tumors usually being asymptomatic. Larger tumors produce swelling, which can expand the cortex and be quite pronounced.Ameloblastic Fibroma: Radiographic Features
Generally, these lesions appear as either a unilocular or multilocular radiolucency. Approximately, 50 % are associated with an unerupted tooth.Ameloblastic Fibroma: Histologic Features
The tumor is composed of a cell-rich mesenchymal tissue resembling the primitive dental papilla admixed with proliferating odontogenic epithelium.Ameloblastic Fibroma Treatment and Prognosis
Most ameloblastic fibromas are treated by conservative surgical excision; however, a 20 % recurrence rate has led some surgeons to recommend a more aggressive approach.Ameloblastic Fibro-odontoma
This lesion is defined as a tumor with general features of an ameloblastic fibroma but containing enamel and dentin.Ameloblastic Fibro-odontoma: Clinical and Radiographic Features
Patient Age: Most common in the 5-12 year age range with a mean of 10 years. Gender Predilection: None. Location: It is more common in the premolar/molar regions of both jaws. Radiographic Features: Usually appears as a well-defined unilocular or rarely multilocular radiolucency with variable amounts of calcified material which is radiopaque. Therefore, it may appear as a mixed, radiolucent-radiopaque lesion.Ameloblastic Fibro-odontoma: Histologic Features
The soft tissue component is identical to the ameloblastic fibroma. The calcified portion consists of foci of enamel and dentin matrix formation in close relationship to the epithelial structures.
Ameloblastic Fibro-odontoma: Treatment and Prognosis
The ameloblastic fibro-odontoma is usually treated by conservative curettage with the lesion separating easily from the surrounding bone. Prognosis is excellent and recurrence is unusual.Ameloblastic Fibrosarcoma
This lesion is considered the malignant counterpart of the ameloblastic fibroma in which the mesenchymal portion shows features of malignancy. The ameloblastic fibrosarcoma may arise de novo or there may be a malignant transformation of an ameloblastic fibroma.Ameloblastic Fibrosarcoma: Clinical and Radiographic Features
Patient Age: The mean age for patients with ameloblastic fibrosarcoma is 26 years. Gender Predilection: Males 2:1. Location: 75 % have occurred in the mandible. Pain and swelling are typically associated with this tumor. Rapid clinical growth is another common feature. Radiographic Features: Appear as an ill-defined, destructive, radiolucent lesion.Ameloblastic Fibrosarcoma: Histologic Features
The epithelial component of this tumor appears histologically benign. The mesenchymal portion is highly cellular. The cells are hyperchromatic and quite pleomorphic. Mitoses are usually prominent.Ameloblastic Fibrosarcoma Treatment & Prognosis
Radical surgical excision is the treatment of choice. The long-term prognosis is difficult to ascertain because of the small number of reported cases.Odontoameloblastoma (Ameloblastic Odontoma): Clinical Features
Extremely rare tumor, thus there is little reliable information. Patient Age: Has been seen in younger patients. Gender Predilection: Unknown. Location: Most cases have been in mandible. Radiographic Appearance: Lesion is a mixed radiolucent-radiopaque, ill-defined one.Odontoameloblastoma: Histologic Features
The epithelial portion of the tumor has the features of an ameloblastoma, most often with a plexiform or follicular pattern. The odontoma portion of the lesion is composed of enamel, dentin, and cementum with either a compound or complex pattern.Odontoameloblastoma: Treatment and Prognosis
Since multiple recurrences have been reported following local curettage, the lesion should be treated as an ameloblastoma with marginal resection. No valid data on long-term prognosis is available due to the small number of cases.Odontoma
The odontoma is the most common odontogenic tumor. It is not a true neoplasm but rather is considered to be a developmental anomaly (hamartoma). Two types of odontomas are recognized: Compound: this type of odontoma is composed of multiple small tooth-like structures. Complex: this lesion is composed of a conglomerate mass of enamel and dentin, which bears no anatomic resemblance to a tooth.Odontoma: Clinical Features
Patient Age: Most cases are recognized during the second decade of life with a mean of 14 years.Gender Predilection: Approximately equal.Location: Somewhat more common in the maxilla. The compound type is more often in the anterior maxilla while the complex type occurs more often in the posterior regions of either jaw.Most odontomas are asymptomatic but large ones may cause expansion of the jaw.Odontomas may block the eruption of a permanent tooth and in these cases are often discovered when “searching for” the “missing” tooth radiographicallyOdontoma: Radiographic Features
In the later stages it appears as a well-defined radiopaque appearance. The compound type shows apparent tooth shapes while the complex type appears as a uniform opaque mass with no apparent tooth shapes present.Odontoma: Histologic Features
The compound odontoma is composed of enamel, dentin and cementum arrange in recognizable tooth forms; some enamel matrix may be retained in immature and hypomineralized specimens. The complex odontoma is composed of enamel, dentin and cementum but these tissues are arranged in a random manner that bears no morphological resemblance to a tooth.Odontoma: Treatment and Prognosis
Odontomas are treated by simple local excision and the prognosis is excellent.Tumors of Odontogenic mesenchyme
(Central) Odontogenic Fibroma: Clinical FeaturesPatient Age: Patients have ranged in age from 9-80 years old with a mean of 40 years. Gender Predilection: Females more . Location: Sixty percent occur in the maxilla where most are located anterior to the first molar. While in the mandible, approximately 50 % occur in the posterior jaw. Small odontogenic fibromas are usually asymptomatic. The larger lesions may be associated with localized bony expansion of the jaw or with the loosening of adjacent teeth.
Odontogenic Fibroma: Radiographic Appearance
The odontogenic fibroma usually appears as a well-defined, unilocular radiolucency. Larger lesions are often multilocular. Root resorption is common.Odontogenic Fibroma: Histologic Features
The odontogenic fibroma is composed of stellate fibroblasts arranged in a whorled pattern with fine collagen fibrils and a lot of ground substance. Foci of odontogenic epithelium may or may not be present.Odontogenic Fibroma: Treatment and Prognosis
The odontogenic fibroma is usually treated by enucleation and curettage. There have been few recurrences, the prognosis is good.
Peripheral Odontogenic Fibroma (POF): Clinical features
Patient Age: POFs are seen over a wide age range. Gender Predilection: This is unknown. Location: Most POFs occur on the facial gingiva of the mandible. POFs generally present as firm, slow-growing, usually sessile masses covered by normal-appearing oral mucosa. They may cause tooth displacement.POF: Radiographic & Histologic Features
Radiographic Appearance: The lesion does not involve the underlying bone. The POF is histologically similar to the central odontogenic fibroma.POF: Treatment and Prognosis
Local surgical excision is the treatment of choice and the prognosis is excellent. There is little to no tendency for recurrence.Odontogenic Myxoma: Clinical and Radiographic Features
Patient Age: 10-50 years with a mean around 30 years. Gender Predilection: Reported to be about equal. Location: May occur in any area of the jaws but more common in the mandible. Radiographic Appearance: Radiolucent lesion often with a multilocular appearance. The borders may be indistinct.Odontogenic Myxoma: Histologic Features
The tumor is composed of loosely arranged stellate, spindle-shaped and round cells in an abundant, loose myxoid stroma with few collagen bundles.Odontogenic Myxoma: Treatment and Prognosis
Small odontogenic myxomas are treated by curettage, while larger lesions may require surgical resection. Odontogenic myxomas are not encapsulated and tend to infiltrate adjacent tissues. Recurrence rates of up to 25 % are reported. Overall, the prognosis is good for most odontogenic myxomas.