1. Tumors of Mandible Dr. Ahmed Khan Sangrasi,
Assist. Prof, Dept. Of Surgery ,
LUMHS, Jamshoro

3. Odontogenic Tumors Ameloblastoma Adenomatoid Odontogenic Tumor: (AOT)
Calcifying Epithelial Odontogenic Tumor:  (CEOT) or Pindborg tumor
Keratinizing and Calcifying Odontogenic Cyst: (KCOC),  or Gorlin cyst
Odontogenic Myxoma
Ameloblastic Fibroma
Ameloblastic Fibro-Odontoma
Complex Odontoma
Compound Odontoma
Cementoblastoma

4. 1.Ameloblastoma
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 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

5. 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

6. image ; Incisional biopsy revealed the lesion to be an ameloblastoma
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.

8. Symptoms:
Noticed as an incidental finding on radiographs taken for other purposes
The first symptom is usually painless bony expansion.

9. Radiographic findings
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.

10. Histologic characteristics
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

11. Treatment 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.

12. 2. Adenomatoid Odontogenic Tumor: (AOT)
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

13. 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.

14. Radiographic findings
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.

15. Histologic characteristics
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.

16. Treatment 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.

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

18. Radiographic findings
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

19. Treatment: 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.

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

21. Radiographic findings:
These are nondescript radiolucencies that may contain flecks of opacity
They may become quite large if not discovered serendipitously.

22. Histologic characteristics
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.

23. 5. Odontogenic Myxoma:
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.

24. Radiographic findings :
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).

25. Histologic characteristics:
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.

26. Treatment:
As with ameloblastoma, this lesion is treated with block excision
Recurrences occur although with somewhat less frequency than with ameloblastoma

27. 6. Ameloblastic Fibroma
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.

28. Radiographic findings:
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.

29. Histologic characteristics
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.

30. Treatment
The treatment of this lesion is block excision with a border of normal bone
With simple enucleation, recurrence rates of % have been reported.
Sarcomatous change (ameloblastic fibrosarcoma) has also been reported with recurrence or inadequate excision.

31. 7.Ameloblastic Fibro-Odontoma:
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.

32. Radiographic findings
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

33. Histologic characteristics
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.

34. Treatment
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.

35. 8.Complex Odontoma;
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.

36. Radiographic findings
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.

37. Histologic characteristics
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.

38. 9.Compound Odontoma: 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.

39. Histologic characteristics
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.

40. 10.Cementoblastoma:
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.

41. Radiographic findings
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

42. Histologic characteristics
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.