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Ameloblastoma

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odontogenic tumor, classification, clinical features, management

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Ameloblastoma

  1. 1. AMELOBLASTO MA SUBMITTED BY MANJARI RESHIKESH IV BDS PART II DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY
  2. 2. TUMOUR- DEFINITION  A tumour or neoplasm is defined as an abnormal mass of tissue , the growth of which is uncontrolled & uncoordinated with that of normal tissue & persist in the same excessive manner even after the cessation of stimulus that evoked the change.- R.A. WILLIS
  3. 3. CLASSIFICATION Based on origin • Odontogenic • Non Odontogenic Based on its nature • Benign • Malignant
  4. 4. ODONTOGENIC TUMORS A. Benign 1. Odontogenic epithelium without odontogenic mesenchyme 1. Ameloblastoma 2. Squamous odontogenic tumor 3. Calcifying epithelial odontogenic tumor 4. Adenomatoid Odontogenic tumor 2. Odontogenic epithelium with odontogenic ectomesenchyme with or without hard tissue formation 1. Ameloblastic fibroma 2. Ameloblastic fibro-dentinoma 3. Ameloblastic fibro odontoma 4. Odontoameloblastoma 5. Calcifying odontogenic cyst 6. Complex odontoma 7. Compound odontoma
  5. 5. 3.Odontogenic ectomesenchyme with or without included odontogenic epithelium 1. Odontogenic Fibroma 2. Myxoma 3. Cementoblastoma B. Malignant 1. Odontogenic carcinoma 1. Malignant ameloblastoma 2. Primary intra-osseous carcinoma 3.Clear cell odontogenic carcinoma 4.Ghost cell odontogenic carcinoma 2.Odontogenic Sarcomas  Amelobastic Fibrosarcoma  Amelobastic fibro-dentinosarcoma  Ameloblastic fibro-odontosarcoma
  6. 6. AMELOBLASTOMA “Usually unicentric,nonfunctional,intermitte nt in growth ,anatomically benign and clinically persistent” - Robinson • True neoplasm of enamel organ type tissue • Second most common odontogenic neoplasm
  7. 7.  Originated from early english word ‘amel’ meaning ‘enamel’ and greek word ‘blastos’ meaning ‘germ’  It was recognised 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
  8. 8. CLASSIFICATION Clinical classification  Central (Intraosseous) 1. Conventional/ Multicystic/Solid (most common) 2. Unicystic 3. Peripheral (extraosseous) 4. Pituitary ameloblastoma 5. Malignant ameloblastoma Based on histological type 1. Follicular ameloblastoma 2. Plexiform ameloblastoma 3. Acanthomatous ameloblastoma 4. Granular cell ameloblastoma 5. Basal cell type of ameloblastoma 6. Desmoplastic ameloblastoma
  9. 9. ETIOLOGY Traumatic episodes: Extraction, cystectomy, fractures Infections Dietary deficiency: vitamin D deficiency,Lack of protein intake Virus infection
  10. 10. Ameloblastoma is believed to be derivedfrom a) Cell rest of enamel organ, either remnants of dental lamina or Hertwig’s sheath, the epithelial rest of Malassez. b) Epithelium of odontogeniccysts, particularly the Dentigerous cyst & odontomas. c) Disturbance to developing enamel organ. d) Basal cells of the surface epithelium of the jaws. e) Heteropic epithelium in other parts of bodyespecially the pituitary gland. PATHOGENESIS
  11. 11. Age: 20-50 years Sex: no significant sex predilection Race: more common in blacks than in white race. Site: mandible > maxilla(more than 80% mandible)  with in mandible molar ramus area is affected three times more commonly than premolars & anteriors. CLINICAL FEATURES
  12. 12. RELATIVE DISTRIBUTION OF AMELOBLASTOMA
  13. 13. SIGNS AND SYMPTOMS • it starts as a slow growing , painless, hard, non tender, ovoid swelling which often enlarges in size as it causes little discomfort in early stage. • Facial assymetry • Mobilty of teeth and exfoliation • Ill fitting dentures • Pain or paresthesia if impinges on nerve • Inability to occlude • Ulcerations
  14. 14. In the absence of treatment, • it may be extremely disfiguring ,fungating and ulcerative like carcinoma • Keeps on enlarging and cause “egg shell crackling’’& fluctuation • Palpation elicit hard sensation or crepitus. • Not encapsulated • Invades surrounding tissues • Bone destruction is a common finding by invasion to bone marrow • Root resorption is caused
  15. 15. SIZE: small as 1cm to large as 16 cm SPREAD: local invasion  Causes expansion of bone than destruction. • infiltrates cancellous bone but never cortical bone  MURAL AMELOBLASTOMA:  ameloblastoma from dentigerous cyst • MAXILLARY AMELOBLASTOMA: • common in tuberosity. more dangerous as 1. It may cause nasal obsturction 2. proptosis of eye 3. Damage vital structures 4. Involve cranial base 5. Cause gross facial distortion
  16. 16. VICKER’S AND GORLIN’S CRITERIA 1.Tall columnar cell 2.Hyperchromatic nucleus 3.Palisaded nuclei 4.Reverse polarity of nuclei 5.Subnuclear vacuole formation HISTOLOGY
  17. 17. HISTOLOGIC FEATURES 6 HISTOLOGICSUBTYPES  Follicularameloblastoma  Plexiformameloblastoma  Acanthomatous ameloblastoma  Granular ameloblastoma  Basal celltype of ameloblastoma  Desmoplastic ameloblastoma
  18. 18. *Small discrete islands of tumour cells. *Peripheral layer of cuboidal or columnar cells. *Nuclei well polarized. *Resembles ameloblast. *Cyst formation is relatively common. *Stellate reticulum like cells prominent enclosed by columnar or cuboidal cells
  19. 19. Plexiform ameloblastoma  Ameloblast like cells arranged in irregular masses.  Networks of interconnectingstrands of cells.  Each strands bounded by layer of columnar cells.  In b/w thesepresent stellate reticulumlike tissues less prominent compared to follicular ameloblastoma.  Areas of cystic degenerationis common.
  20. 20. 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 may be observed
  21. 21. 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
  22. 22. BASAL CELL AMELOBLASTOMA • Bear resemblance to basal cell carcinoma of skin • Rarest histologic subtype • Hyperchromatic ,less columnar,arranged in sheets without peripheral palisading
  23. 23. 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 hyalinised stroma
  24. 24. UNICYSTIC AMELOBLASTOMA single cystic cavity showing ameloblastomatous differentiation Age: The patients are younger than those with the solid/multicystic form ie around 20 yrs Sex Predilection: equal Location: 90 % occur in the mandible usually in the posterior region Typically surrounds the crown of unerupted mandibular third molar and resembles dentigerous cyst
  25. 25. HISTOLOGY ACKERMANN CLASSIFICATION Luminal type: the tumor is confined to the luminal surface of the cyst by fibrous connective tissue partially or totally Intraluminal: the tumor nodules projects from the cystic lining Mural: the tumor infiltrates the fibrous cystic wall.(high recurrence rate)
  26. 26. RADIOGRAPHIC FEATURES • Presents a unilocular or multilocular radiolucency in diff forms and shapes • 50% multilocular,2% peripheral and 6% unicystic lesions • Multilocular radiolucency with compartmentalised appearance due to bony septa (HONEY COMB or SOAP BUBBLE APPEARANCE) • Root resorption and tooth displacement Soap bubble appearence Honey comb appearence
  27. 27. • Small / large unilocular or multilocular lesion may show unerupted tooth • Buccolingual cortical expansion( hollowing out)
  28. 28. C- soap bubble D- honey comb
  29. 29. UNICYSTIC TYPE Well defined radiolucent lesion with minimal peripheral sclerotic border Mimics dentigerous cyst Associated with impacted 3rd molar In adv stage thinning of cortical bone seen
  30. 30. • Maxillary lesions involve maxillary sinus and make it more opacified appearance • CT SCAN and 3d reconstructions
  31. 31. PERIPHERAL AMELOBLASTOMA Rare type Develops in softtissue of gingiva and mucosa Non invasive Clinical features *Younger individuals *Mandible>maxilla *In premolar region *Apperas as a nodule on the gingiva/ mucosa *Size 3mm-2cm
  32. 32. Pituitary ameloblastoma PITUITARY AMELOBLASTOMA • Craniopharyngioma/Rathke’s pouch tumor. • Neoplasm involving CNS. • Grows as a pseudo encapsulated mass in the suprasellar area and destroys pituitary gland. • Clinical features- • endocrine disturbances,drowsiness& even toxic symptoms.
  33. 33. MALIGNANT AMELOBLASTOMA • Malignant transformation of ameloblastoma • Rare lesion • Almost exclusively in mandible • Mean age: 28-32 yrs • Common sites for metastasis; Lungs,spleen,kidney,ileum
  34. 34. Investigations • RADIOGRAPHS • Biopsy • CT • MRI • ultrasound
  35. 35. TREATMENT • Treatmentoptions include: a) Radical& conservativesurgicalexcision. b) En bloc resection c) Segmentalresection d) Curettage e) Chemical& electrocautery f) chemotherapy g) radiation.
  36. 36. SIMPLE EXCISION/ENUCLEATION In case of peripheral ameloblastoma,simple excision of the lesion is performed
  37. 37. ENUCLEATION&CURETTAGE • In peripheralameloblastoma,simpleexcisionis performed • Meansremovalofthetumorby scraping it fromthe surrounding normaltissue. • Curettagegiven a cure rateofonly 10% • 60-90%ofrecurrence rate Complicationsofcurettage • Seeding into lungs • Malignanttransformation • Failureofcurettageis probably relatedtothe factthatthe nestoftumorcellsextendbeyond clinical&radiographic marginsofthelesion. • Thereforeimpossibletoeradicatethe lesion by scraping procedure.
  38. 38. ENBLOC RESECTION • Meansremoval oftumorwith arim ofuninvolved bonebut maintainingthe continuityofjaw. • Frequentlyusedtherapeuticmeasure. • Kramer1963 reported thatalthoughthereis a diffuseinvasion of cancellousspaces ofthe bonemarrowby fingerlikeprojectionsit does not invadehaversian systemofcompactbone. • A 1-2cm marginbeyond theradiographic limitis consideredthe minimumacceptablemarginfor resection. • Leastno of recurrences reported
  39. 39. SEGMENTAL RESECTION • Means removal of segmentof themaxilla/ mandible up to & includinghemisection or more. • Includeshemimaxillectomy& hemimandibulectomy. • Most Commonly used treatment. • Least chance of recurrence. • It is noted thatthe lesion most likely to recur aftersegmental resection are thoseover 5cm.
  40. 40. Chemotherapy • May be sensitive to platinum agents • May have role in improvement in non surgical patients • Eg; cyclophosphamide,cisplatin,vinblastine,methotr exate etc
  41. 41.  Desiccation / electro coagulationof the lesion includingvarious amountof surroundingnormal tissues.  Not been commonlyused as primary mode of therapy.  Much more effectivetherapy than curettage.  50% recurrence rate.  Because of poor results –not been used as a sole methodof treatment. electrocautery
  42. 42. Radiation therapy • Ameloblastoma is generally radioresistant • Post operatively in pts with gross/microscopic residual disease • Recurrent disease • Pts who are poor candidates of surgery
  43. 43.  rehabilitation with obturator in maxilla POST OPERATIVE MANAGEMENT
  44. 44. Reconstruction with graft
  45. 45. RECONSTRUCTION WITH TITANIUM PLATES AND SCREWS
  46. 46. Simple curettage- 90% recurrence rate. Ameloblastoma of maxilla – more aggressive – poor prognosis. PROGNOSIS
  47. 47. Ameloblastic fibroma Odontogenic myxoma Central giant cell granuloma Dentigerous cyst OKC DIFFERENTIAL DIAGNOSIS
  48. 48. Daniel.M.Laskin – oral & maxillofacial surgery- volume 2 Shafer’s textbook of oral pathology- 7th edition REFERENCES
  49. 49. THANK YOU

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