Tumors of Mandible Dr. Ahmed Khan Sangrasi,

Assist. Prof, Dept. Of Surgery , LUMHS, Jamshoro

1. Ameloblastoma2. Adenomatoid Odontogenic Tumor: (AOT)3. Calcifying Epithelial Odontogenic Tumor:

 (CEOT) or Pindborg tumor4. Keratinizing and Calcifying Odontogenic

Cyst: (KCOC),  or Gorlin cyst5. Odontogenic Myxoma6. Ameloblastic Fibroma7. Ameloblastic Fibro-Odontoma8. Complex Odontoma9. Compound Odontoma10. Cementoblastoma

Odontogenic Tumors

An entirely epithelial tumor arising from the dental lamina, Hertwig sheath, the enamel organ, or the lining of dental follicles/dentigerous cysts

Is the most common epithelial odontogenic tumor Usually occur in individuals aged 20-40 years However, the unicystic variant most often occurs

in adolescents

Lesion occurs in both the maxilla and mandible Posterior mandible is the most common location

1.Ameloblastoma

Only 20% of lesions are found in the maxilla Distributed equally between males and

females Generally is not classified as a malignant

lesion (a rare malignant variant exists), it is extremely aggressive and infiltrative

Should be considered a low-grade or indolent malignancy, similar to basal cell carcinoma.

Generally does not metastasize but is slow growing, persistent, and hard to eradicate

image ; Incisional biopsy revealed the lesion to be an ameloblastoma. Treatment consisted of segmental resection of the entire mandible from the condyle to the area of the second premolar. The lateral and internal aspects of the resected specimen are depicted.

Noticed as an incidental finding on radiographs taken for other purposes

The first symptom is usually painless bony expansion.

Symptoms:

Typically appear as an expansile multilocular radiolucency in the area of the lower third molar, but they may be found anywhere in the jaws

Image:  The second radiograph depicts the appearance of the lesion at the second presentation.

Radiographic findings

Does not have a capsule. Neoplastic component is purely epithelial and

resembles the cap stage of odontogenesis Lesion may have a reactive connective tissue

component that is not neoplastic This is a nonfunctional tumor, ie, it does not

induce the surrounding connective tissue, which in turn is unable to induce enamel formation

In effect, these tumors represent arrested odontogenesis

Histologic characteristics

Surgical excision with wide free margins Appropriate reconstruction may be performed at the same

time. All patients with ameloblastoma, regardless of surgical

treatment method or histologic type, must be monitored radiographically throughout their lifetime

If excision is inadequate, recurrence is common. 1-cm clear margins are considered the standard. This may

be accomplished with block or segmental resection, depending on the relationship of the lesion to the inferior cortical border.

For peripheral ameloblastoma, a more conservative excision with close clinical follow-up is the standard of care.

Treatment

Is a fairly uncommon tumor Usually can be easily identified from its

clinical and radiographic appearance It often is remembered as the "two-thirds

tumor." It most commonly occurs in the second and

third decades of life (12-20 y). Two thirds of the cases occur in the anterior

maxilla, one third occur in the anterior mandible, and it is never found posterior to the premolars

2. Adenomatoid Odontogenic Tumor: (AOT)

Two thirds of the cases occur in females, and two thirds of the cases are associated with an impacted tooth (usually the cuspid).

This tumor originates from the reduced enamel epithelium of the dental follicle and histologically reproduces the IEE ( inner enamel epithelium)

It is generally asymptomatic but may present with mild swelling or in association with a clinically missing tooth.

Lesion generally appears as a well-demarcated radiolucency

In 75% of cases, it is associated with an unerupted tooth, usually the canine

May contain radiopaque flecks, which represent calcified material.

If associated with a tooth, it generally attaches to the tooth further apical on the root than the typical dentigerous cyst.

Radiographic findings

Technically, this is a hamartoma rather than a true neoplasm because it has a limited growth potential

 It has a thick fibrous capsule filled with a proliferation of epithelial elements that form nodules and ductlike structures .

 In the absence of connective tissue to induce the formation of enamel, ultimately leave areas of dystrophic calcification and amyloid.

Histologic characteristics

The recommended treatment of these lesions is simple removal

If left alone, these structures probably involute. 

However, they can become quite large. Most are removed at biopsy  If it is incompletely removed at biopsy, the

literature suggests that the remainder of the lesion degenerates

 They are not known to recur.

Treatment

Is a benign infiltrative odontogenic tumor that is one of the rarest

Named after Jens Pindborg, the Danish oral pathologist It is most often found in the mandibular molar/premolar

region, but 33% of cases are found in the maxilla  It is associated with an unerupted or impacted tooth in

50% of cases CEOT is an infiltrative neoplasm and causes destruction

with local expansion It is derived from the stratum intermedium and has a

lower growth potential than ameloblastoma. Not surprisingly, it is less aggressive than ameloblastoma.

3. Calcifying Epithelial Odontogenic Tumor:  (CEOT) or Pindborg tumor:

These lesions can be radiolucent, but they more characteristically are mixed lucent and opaque masses, exhibiting a snow-driven appearance.

Histologic characteristics : Histologic view of this lesion is worrisome

because it appears as invasive infiltrative islands in bone

These islands look like pure squamous cells with a high degree of nuclear pleomorphism

However lack of mitotic figures help to distinguish this lesion from squamous cell carcinoma

Radiographic findings

The treatment of this lesion is complete surgical excision

The recurrence rate for CEOT is 4% The lesion is slow growing and requires

long-term follow-up monitoring for recurrence (at least 5-10 y).

No cases of malignant transformation are reported.

Treatment:

Is not actually a cyst but rather a neoplasm with cystic tendencies

Some KCOC lesions are actually solid This is a very rare lesion with no age, sex, or location

predilections. May be found anywhere in the jaws, and one fourth of

lesions are found in peripheral soft tissue (eg, gingiva).  If KCOC is not discovered as an incidental finding on

radiographic examination, the earliest clinical presentation usually is a localized swelling.

These lesions arise from a more mature enamel epithelium than ameloblastoma, and, accordingly, they have less growth potential.

4. Keratinizing and Calcifying Odontogenic Cyst: (KCOC),  or Gorlin cyst:

These are nondescript radiolucencies that may contain flecks of opacity

They may become quite large if not discovered serendipitously.

Radiographic findings:

Lesions are lined by an epithelium that is similar in appearance to ameloblastoma

Appears somewhat similar to the unicystic ameloblastoma, with masses of keratinized squamous epithelial cells within the SR(stellate reticulum)

However, these cells have no nuclei and are called ghost cells.

Simply, this lesion represents enamel epithelium that has a tendency to mature but is unable to form enamel

Treatment: These lesions are surgically removed and rarely recur

after excision.

Histologic characteristics

This is a benign infiltrative lesion that is clinically indistinguishable from ameloblastoma

It is found in tooth-bearing areas, and a slight predilection for the mandible exists

 It generally appears in the early third to fourth decades of life as a slow-growing expansile lesion

If odontogenic myxoma is left untreated, it is invasive and destructive

It is derived from dental mesenchyme (papilla) or follicle.

5. Odontogenic Myxoma:

The radiographic appearance of this lesion is not distinctive.

 It appears quite similar to ameloblastoma (eg, multilocular radiolucency), though some authors believe that the individual loculations are somewhat smaller in odontogenic myxoma (myxofibroma).

Radiographic findings :

A few stellate fibroblasts with copious amounts of hyaluronic acid, scant collagen fibrils, and no capsule describe the histologic appearance of this lesion.

The hyaluronic acid component stains with Alcian blue, reminding one of the appearance of Wharton jelly.

This lesion looks like developing pulp and may be confused with a developing third molar.

Histologic characteristics:

As with ameloblastoma, this lesion is treated with block excision

Recurrences occur although with somewhat less frequency than with ameloblastoma

Treatment:

Is a true mixed tumor arising from a combination of 2 embryonic tissues

The epithelial component is able to induce mesenchyme but not to the extent of developing dental hard tissues

It is a relatively uncommon tumor of young people (aged 5-20 y);

75% of ameloblastic fibromas are found in the posterior mandible in the area of a developing tooth.

It is benign and expansile, growing as a pushing front rather than invading surrounding tissues.

6. Ameloblastic Fibroma

This lesion appears as a uniocular or bilocular radiolucency, most often in the posterior mandible.

Appearance is identical to that of unicystic ameloblastoma, and both lesions should be differential diagnoses because they affect similar age groups and have similar clinical and radiographic appearances

Histologic examination differentiates the two.

Radiographic findings:

The epithelial component of this lesion is almost identical to that of ameloblastoma;

However, the connective tissue component looks like dental pulp. It is a young, cellular, homogenous connective tissue without much dense collagen

The epithelial and connective tissue components grow together inside a capsule.

Histologic characteristics

The treatment of this lesion is block excision with a border of normal bone

With simple enucleation, recurrence rates of 20-40% have been reported.

Sarcomatous change (ameloblastic fibrosarcoma) has also been reported with recurrence or inadequate excision.

Treatment

Is an extremely rare odontogenic lesion that develops dental hard tissues (eg, dentin, enamel, cementum)

It appears most often before age 20 years and has a slight predilection for the premolar area in either jaw

Although these lesions can become quite large, they generally do not have much growth potential.

7.Ameloblastic Fibro-Odontoma:

Appears as a well-demarcated radiolucency with a large central opacity

Lesions almost always are found in association with a tooth.

Some similarity exists in radiographic appearance to that of the Pindborg tumor and Gorlin cyst because this is a mixed radiolucent/radiopaque lesion

Radiographic findings

This lesion has the histologic characteristics of ameloblastic fibroma

However, epithelial induction of connective tissue occurs to the point of histodifferentiation, leading to presence of dentin, enamel, and/or cementum in the microscopic presentation.

Histologic characteristics

Surgical excision of ameloblastic fibro-odontoma is the usual proposed treatment

These lesions do not often recur. The literature contains some support for sarcomatous change with recurrence.

Treatment

Represent further histologic differentiation of the odontogenic pluripotential epithelium

Findings from this lesion resemble those of ameloblastic fibro-odontoma but extended one step further

The epithelium in this lesion has involuted, leaving disorganized dental hard tissues in place

These are common lesions, and they persist throughout life

They are usually detected in adolescence and have a predilection for the mandibular molar regions; however, they can be found in other areas of the jaws.

8.Complex Odontoma;

Lesions are generally described as sunburst radiopacities surrounded by a thin, uniform, radiolucent rim. 

Have some superficial resemblance to the radiographic description of osteosarcoma, 

The association with a tooth, the clear demarcation of the lesions' borders, and the lack of pain and/or swelling serve to delineate this very benign lesion from osteosarcoma.

Radiographic findings

Physiologic reduction of the ameloblastic epithelium is found.

A mixed honeycomb presentation of enamel, cementum, dentin, and pulpal tissue is present

Treatment Simple removal or radiographic observation

is the method of treatment These lesions do not recur.

Histologic characteristics

This is the most common odontogenic tumor.  It is most commonly found in the maxillary

anterior alveolar bone But may be located anywhere within the tooth-

bearing segments of the jaws. It is often responsible for preventing normal

tooth eruption, thus it is usually discovered during adolescence.

Radiographic findings Multiple tiny toothlike structures are contained

within a fine radiolucent rim.

9.Compound Odontoma:

Histology of compound odontomas approaches normal tooth structure

Gross clinical examination is usually sufficient for diagnosis.

Treatment

Simple removal is the method of treatment These lesions do not recur.

Histologic characteristics

Cementoblastoma, as distinguished from cementoma, is a true neoplasm of cementum

This benign neoplasm is rare and is usually observed in patients younger than 25 years

It is most often found in association with the apex of the mandibular first molars (50% of lesions), and it is never found in association with the anterior dentition.

The lesion is usually asymptomatic, although occasionally the associated tooth may be slightly sensitive to percussion.

10.Cementoblastoma:

A round opaque sunburst mass attached to the apex of a tooth that is well-demarcated and surrounded by a thin radiolucent rim is observed

The lesion obscures the lamina dura Sometimes confused with condensing

osteitis, a common lesion resulting from low-grade periapical irritation that stimulates bone growth

Radiographic findings

Plump cementoblasts separated by cemental partitions form the histology of this encapsulated lesion.

Treatment Removal of attached tooth and tumor is the

method of treatment. No recurrences are reported.

Histologic characteristics