Ameloblastoma

ameloblastoma ,

1. A meloblastoma By: Mohamed Saber

2. Ameloblastoma Definition Etiology Origin Types Clinical features(incidence) Clinical presentaion Radiographic presentation Histopathological findings Differential diagnosis treatment

3. It is a benign but invasive epithelial odontogenic neoplasm. Consisting of proliferating odontogenic epithelium lying in fibrous stroma

4. etiology Unknown , but possible causal factors suggested : Truama or inflamation Oral infection,extraction,injury to teeth or jaws Irritation resulting from eruption of the third molar

5. Origin of ameloblastoma The precise point of origin of ameloblastoma is unknown ,the origin might be from: Epithelial rests of serre or malassez Epithelial lining of non neoplastic odontogenic cyst( dentigerous cyst) Direct from oral epithelium

6. types Conventional solid or multicystic 94% Unicystic (mural) 5% Peripheral or extraosseous 1%

7. incidence It’s the most common epithelial odontogenic neoplasm. It comprises about 1% of all oral tumors. Mandible>maxilla 85%:15% in mandible: 70% in molar- ramus area, 20%in premolar area, 10% in incisor region

8. incidence In the maxilla: Tumor found in the posterior region Age predilection : Fourth and fifth decades The tumor can occur in children or in old age

9. Clinical presentation In the early stages : ameloblastoma grows slowly &silently without clinical signs. in advanced stages: neoplasm expand cortical plates thinning of bone (egg shell crackling )erodes them invades the soft tissue At this point ameloblastoma present clinically as a smooth surfaced local expansion of the jaw producing asymmetry.

10. Clinical presentation Lesion may be composed of solid tumor,cystic areas,or booth. Tipping or loosening of teeth,involvement of inf. Alveolar nerve may occur. Draining sinuses,unhealed extraction sockets associated with granulation tissue within the socket,bleeding , trismus & other dental problems may be the chief complain

11. Clinical presentation Max. ameloblastoma : Nasal obstruction is 1 st symptoms Potentially lethal if sinus involved or tumor invade the bone into soft tissues due to: Bone is not compact, easily invaded Proximity to: nasal cavity&sinuses orbital&pharyngeal tissues vital structures at base of skull This factors also complicate comlete removal

12. Radiographic presentation Ameloblastoma is osteolytic lesion Unilocular or multilocul radiolucency Multilocular lesion may be : Honey combed (small loculation ) Soap bubble (large loculation ) Crtical bone may be spread &expanded or destroyed. Unerrupted tooth may be present(resembling dentigerous cyst)

13. Radiographic presentation Root resorption of associated teeth. Maxillary tumors produce a monocystic cavity in most instances.

14. Histopathological findings Ameloblastoma can be classified into: Follicular ameloblastoma or plexiform ameloblastoma . Variant s of follicular ameloblastoma : Cystic type Basal cell type Acanthomatous type Dysmoplasatic type

15. Histopathological findings Follicular ameloblastoma : Made of epithelial follicles resembling enamel organ in mature fibrous c.t . stroma . Epithelial follicles consist of peripheral tall columnar cells( ameloblast like cells)& central core of loosely arranged angular cells (the stellate reticulaum like cells)

16. Histopathological findings Plexiform ameloblastoma : The epithelium is arranged in a network of anastomosing strands and cords with the same cell layers as follicular ameloblastoma .

17. Differential diagnosis Other odontogenic tumors: Ameloblastic fibroma,odontogenic myxoma . Non odontogenic tumors: Central giant cell granuloma,aneurysmal bone cyst. Odontogenic cysts: Dentigerous cyst,odontogenic keratocyst

18. Treatment Treatment of ameloblastoma ranges from conservative curettage to radicular resection. Treatment varies according to site,size&characteristics of the ameloblastoma Curettage En-block resection Segmental resection

19. curettage It is the removal of the tumor by scraping it from the surrounding normal tissue. It is the least desirable form of therapy. Failure of curettage is due to extension of tumor cell nests beyond the clinical& radiographic margins of the lesion,therefore it is impossible to eradicate by scraping procedure.

20. En –block resection It is removal of the tumor with a rim of uninvolved bone safe margin,but with maintaining the continuity of the jaw. It is frequently used for ameloblastoma,although there is a diffuse invasion of cancellous spaces of bone marrow by finger like projections,tumor tissue doesn’t invade the haversian system of compact bone,thus compact bone of mandible can be eroded but it is less likely to be invaded.

21. Segmental resection Segmental resection including hemimaxillectomy & hemimanibulectomy has been the most commonly used treatment for ameloblastoma . Most authors who advocate this method have had the least number of recurrence.

22. Unicystic (mural) ameloblastoma Its formed in the wall of a dentigerous cyst Its ranked next to dentigerous cyst as the most frequently occuring pathologic pericoronal radiolucency . The terms mural or unicystic are used to identify this type ,although unicystic ameloblastoma can occur in other locations &not contacted to teeth

23. Unicystic (mural) ameloblastoma It represent about 5% of all ameloblastoma . The conventional ameloblastoma and mural ameloblastoma are similar in predilection for gender( males&females equally affected)& Site( mand . 3 rd molar region) However the mural variety occur in younger age gp .(2 nd &3 rd decades) Can be related to other types of cyst( radicular,primordial,residual --, globulomaxillary )

24. Unicystic (mural) ameloblastoma in early stage asymptomatic,undetected untile pericoronal radiolucency is seen on routine radiograph. Slowly enlarged,slight non tender sweeling appear clinically. If bone destruction occur,palpation discloses softer areas.

25. Unicystic (mural) ameloblastoma Radiographically : If haziness&thinning of hyperostotic radioopaque rim of pericoronal radiolucency Tumor invade the capsule of the cyst &start to infiltrate the bone trabeculae .

26. management Before undertaking surgical procedure of pericoronal radiolucency , differential diagnosis bet. mural( unicystic ) &conventional ameloblastoma should be completed. At surgery the cyst should be enucleated,and if mural mass is discovered flag it with suture to enable the pathologist for further investigation.

27. management If pathologist examination establishes the mass as ameloblastoma that has not penetrated the basement membrane no further surgery is done. If the neoplasm has penetrated the basement membrane more the bone should be removed with curettage. In all cases careful periodic follow- up is always indicated.

28. Peripheral( extraosseous ) ameloblastoma Origin: basal layer of oral epith.&extraosseous portion of epith . Rests of serre . Site: commonly affect gingiva & alveolar mucosa mandible> maxilla Micoscopically it looks like acanthomatous type of basal cell carcinoma of the skin. Management: excision. Behavior: less invasive than intraosseous ameloblastoma .