MULUNGUSHI UNIVERSITY-SOM AMELOBLASTOMA.pptx

Ameloblastoma etiology pathophysiology diagnosis and management

1. MULUNGUSHI UNIVERSITY SCHOOL OF MEDICINE 5 TH YEAR MBCHB MAXILLOFACIAL ROTATION AMELOBLASTOMA Dr. Lukulula E. Mwanza Dip.DS(UNZA), BDS(CBU), MPH(UNZA), PhD-Candidate (UNZA) Senior Dental Surgeon HoD – Ndola teaching Hosp Department of Dentistry HoD - Oral & Maxillofacial Surgery unit Honorary Lecturer (CBU-SOM) Honorary Lecturer (Mulungushi University-SOM)

2. CONTENT INTRODUCTION AETIOLOGY CLINICAL FEATURES HISTOLOGICAL VARIANTS INVESTIGATION TREATMENT

3. INTRODUCTION Ameloblastoma is… USUALLY Unicentric, nonfunctional, intermittent in group, anatomically benign and clinically persistent. Robinson True neoplasm of enamel organ type tissue Second most common odontogenic neoplasm

4. HI STORY Originated from early English word ‘ amel ’ meaning ‘enamel’ and a Greek word ‘ blastos ’ meaning ‘germ’ It was recognized by Cusack in 1827 Named as adamantinoma by Louis Charles Malassez because of its histological similarity with adamantinoma of long bones Coined as ameloblastoma by Churchill and Ivey in 1934 First detailed description given by Falkson in 1879

5. ETIOLOGY Traumatic episodes; Extractions, cystectomy, fractures Infections Dietary deficiency; Vitamin D deficiency, lack of protein intake Virus infection

6. PATHOGENESIS Ameloblastoma is believed to be derived from Cell rest of the enamel organ, either remnants of dental lamina or Hertwig’s sheath, the epithelial rest of Malassez . Epithelium of odontogenic cysts, particularly the dentigerous cyst and odontomas Disturbance to developing enamel organ Basal cells of the surface epithelium of the jaws Heteropic epithelium in other parts of the body especially the pituitary gland

7. CLASSIFICATION Clinical classification C entral (intraosseous) Conventional/Multicystic/Solid-most common Unicyst Peripheral (extraosseous) Pituitary ameloblastoma M alignant ameloblastoma

8. CLASSIFICATION CONT’D 2. Based on histological type Follicular ameloblastoma Plexiform ameloblastoma Acanthomatous ameloblastoma Granular cell ameloblastoma Basal cell type of ameloblastoma Desmoplastic ameloblastoma

9. CLINICAL FEATURES Age: 20-50 years Sex: No significant sex predilection Race: More common in blacks than in whites Site: Mandible molar ramus area is affected three times more commonly than premolars anterior. It may be either solid or unicystic type Usually asymptomatic and discovered either during routine radiological examination or because of asymptomatic jaw expansion

10. SIGNS AND SYMPTOMS It starts as a slow growing, painless, hard, non tender, void swelling which often enlarges in size in early stages Facial asymmetry Mobility of teeth and exfoliation Ill fitting dentures Pain or paresthesia if impinges on nerves Inability to occlude Ulcerations

11. IN ABSENCE OF TREATMENT It may be extremely disfiguring, fungating and ulcerative like carcinoma Keeps on enlarging and cause ‘egg’ shell crackling and fluctuation Palpation elicit hard sensation or crepitus Invades surrounding tissues Bone destruction is a common finding by invasion to bone marrow Root resorption is caused

12. Size: small as 1cm to as large as 16cm Spread: local invasion Causes expansion of the bone than destruction. Infiltrates cancellous bone but never cortical bone MURAL AMEOBLASTOMA Ameloblastoma from dentigerous cyst MAXILLARY AMELOBLASTOMA Common in tuberosity More dangerous It may cause nasal obstruction Proptosis of eye Damage vital structures Involves cranial base Cause gross facial distortion

13. HISTOLOGY VICKER’S AND GORLIN’S CRITERIA Tall columnar cell Hyperchromatic nucleus Palisaded nuclei Reverse polarity of nuclei Subnuclear vacuole formation

14. HISTOLOGIC FEATURES HISTOLOGIC SUBTYPE Follicular ameloblastoma Plexiform ameloblastoma Acanthomatotous ameloblastoma Granular ameloblastoma Basal cell type of ameloblastoma Desmoplastic ameloblastoma

15. FOLLICULAR AMELOBLASTOMA Small discrete islands of tumor cells Peripheral layer of cuboidal or columnar cells Nuclear well polarized Resembles ameloblast Cyst formation is relatively common Stellate reticulum like cells prominent enclosed by columnar cells

16. PLEXIFORM AMELOBLASTOMA Ameloblast like cells arranged in irregular masses Network of interconnecting strands of cells Each strand bounded by layer of columnar cells Areas of cystic degeneration is common

17. ACANTHOMATOUS AMELOBLASTOMA Cells occupying the position of stellate reticulum undergo squamous metaplasia Sometimes with keratin formation in the central portion of tumor islands Usually occurs in follicular type Sometimes keratin pearls maybe observe

18. GRANULAR CELL AMELOBLASTOMA Marked transformation of cytoplasm, usually of stellate reticulum like cells become coarse, granular, eosinophilic appearance Include peripheral columnar or cuboidal cells Hyperchromatism Reverse polarity

19. BASAL CELL AMELOBLASTOMA Bear resemblance to basal cell carcinoma of the skin Rarest histologic subtype Hyperchromatic, less columnar, arranged in sheets without peripheral palisading

20. DESMOPLASTIC AMELOBLASTOMA Found in a dense collagen stroma that is hypocellular and hyalinized Grow in thin strands and cords of epithelium Epithelial proliferation seems to be compressed and fragmented by hyalinized stroma

21. UNICYSTIC AMELOBLASTOMA Single cystic cavity showing ameloblastoma differentiation Age : The patients are younger than those with the solid/multicystic form i.e. around 20years Sex predilection: equal Location; 90% occur in the mandible usually in the posterior region Typically surrounds the crown of the unerupted mandible third molar nd resembles dentigerous cyst

22. HISTOLOGY ACKERMANN CLASSIFICATION Luminal type; tumor is confined to the luminal surface of the cyst by fibrous connective tissue partially or totally Intramural; the tumor nodules projects from the cystic lining Mural; the tumor infiltrates the fibrous cystic wall.(high recurrence rate)

23. RADIOLOGICAL FEATURES Present a unilocular or multilocular radiolucency in different forms and shape 50% multilocular, 2% peripheral and 6% unicystic lesions Multilocular radiolucency with compartmentalized appearance due to bony septa(HONEY COMB or SOAP BUBBLE APPEARANCE) Root resorption and tooth displacement Small/large unilocular or multilocular lesions may show unerupted tooth Buccolingual cortical expansion(hollowing out)

24. UNICYSTIC TYPE Well defined radiolucent lesion with minimal peripheral sclerotic border Mimics dentigerous cyst Associated with impacted 3rd molar In advanced stage thinning of the cortical bone seen

25. PERIPHERAL AMELOBLASTOMA Rare type Develops in soft tissue of gingiva and mucosa Non invasive Clinical features Younger individuals Mandible maxilla Appears as a nodula on the gingiva/mucosa Size 3mm-2mm

26. PITUITARY AMELOBLASTOMA Craniopharyngioma/ rathkes pouch tumor Neoplasm involving CNS Grows as a pseudo encapsulated mass in the suprasellar area and destroys pituitary gland Clinical features Endocrine disturbances, drowsiness and even toxic symptoms

27. MALIGNANT AMELOBLASTOMA Malignant transformation of ameloblastoma Rare lesion Almost exclusively in mandible Mean age:28-32yrs Common site for metastasis: lungs, spleen, kidney, ileum

28. INVESTIGATIONS Radiographs Biopsy CT scan MRI ultrasound

29. TREATMENT Radical and conservative surgical excision En bloc resection Curettage and electrocautery Chemotherapy Radiotherapy

30. POST OPERATIVE MANAGEMENT Rehabilitation with obturator in maxilla Reconstruction with graft Reconstruction with titanium plates and screws

31. PROGNOSIS Simple curettage- 90% recurrence rate Ameloblastoma of maxilla-more aggressive –poor prognosis

32. DIFERENTIAL DIAGNOSIS Ameloblastic fibroma Odontogenic myxoma Dentigerous cyst Central giant cell granuloma

33. REFERENCES Daniel.m.Laskin - oral and maxillofacial surgery volume 2 Shafer’s textbook of oral Pathology-7 th edition