A REVIEW OF AMELOBLASTOMA

1. A REVIEW OF AMELOBLASTOMA By Jolayemi Judith O.M 600l bds CODEH chairman Coll of med. Univ. of lagos

2. Outline Introduction Aetiopathogenesis Clinical features Histopathology Radiographic features Treatment/prognosis Differential diagnosis Case presentation

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

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

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

6. Clinical features

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

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

9. Histopathology cont’d

10. Histopathology cont’d Plexiform type- thin trabeculae of epithelial cells in connective tissue stroma.

11. Histopathology cont’d

12. Histopathology cont’d Acanthomatous type- squamous metaplasia of central core epithelium though, it resembles the follicular type. Basal cell type- rare, there are small darkly staining cells in a trabeculae pattern, but with little palisading at the periphery. Can be mistaken for basal cell carcinomas.

13. Histopathology cont’d Granular cell type- rare, usually resembles the follicular type but tumor islands contain large eosinophilic granular epithelial cells. Desmoplastic type- cells are not standard in appearance. Connective tissue is densely collagenised Clear cell type- more aggressive. Peripheral ameloblastoma- occurs in soft tissue.

14. Histopathology cont’d

15. Histopathology cont’d Ameloblastomas have been subdivided into two subtypes based on their biology and microscopy- Solid or multilocular[ more aggressive and will require more extensive treatment. It also has a high recurrence rate] Cystic or unicystic

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

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

18. Treatment/prognosis cont’d Malignant types of ameloblastomas are rare. They occur in the younger age and appear more in the mandible. They metastasize to lymph nodes or distant organs. There are two subtypes of malignant ameloblastomas: Malignant ameloblastoma Ameloblastsic carcinoma

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

20. Differential diagnosis CEOT Dentigerous cyst OKCyst Central giant cell granuloma Ossifying fibroma . .

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

23. thank you