46. BENIGN ODONTOGENIC TUMOURS OF JAWS

what is the Classification of benign odontogenic tumours?

1. odontogenic epithelium

- ameloblastoma

- squamous

- calcifying

- adenomatoid

- keratocystic

2. epithelium with ectomesenchyme, with or without HDT formation

- ameloblastoma fibroma

- ameloblastoma fibro-dentinoma

- ameloblastoma fibro-odontoma

- odontoma- complex or compound

- odontoameloblastoma

- calcifying cystic

- dentinogenic ghost cell

3. ectomesenchyme with or without odontogenic epithelium

- odontogenic fibroma

- odontogenic myxoma

- cementoblastoma

what is an ameloblastoma?

A benign odontogenic tumour of epithelial origin which behaves aggressively occurring most commonly in mandible

explain the clinical appearance of ameloblastoma

slow growing mass

loose teeth

malocclusion

paraesthesia

pain

what are the forms of ameloblastoma?

solid

peripheral

desmoplastic

unicystic

explain solid ameloblastomas

most common form + has high recurrence

locally aggressive

can grow to extreme sizes

what is a classic radiographic appearance of solid ameloblastoma?

- soap bubble appearance

- multilocular radiolucency

- root resorption

- jaw expansion

what is the treatment for solid ameloblastomas?

Resection is the gold standard -> lowest rate of recurrence

explain peripheral ameloblastomas

- the most rare form

- pedunculate (attached to tissue via a narrow stalk) gingival lesions

- <1.5cm

- doesn't infiltrate bone

what is the treatment for peripheral ameloblastomas?

wide local incision

- we take out the tumour AND include some margins which are healthy

explain desmoplastic ameloblastomas

asymptomatic and slow growing

xray- mixed radiolucent/ radiopaque

what is the treatment for desmoplasmic ameloblastomas?

radical resection {complete removal of lesion + surrounding healthy tissue}

explain unicystic ameloblastomas

common in younger patients

they mimic dentigerous cysts

xray- unilocular radiolucency (less invasive)

what is the treatment for unicystic ameloblastomas?

1. enucleation and curettage

2. resection when they reoccur

what are ameloblastic fibromas?

true tumours- they involve both epithelial and neoplastic tissues

explain the clinical appearance of ameloblastic fibromas

mostly in younger patients

posterior mandible is affected mostly

associated with unerupted tooth

xray- small and unilocular OR large and multilocular

what is the treatment for ameloblastic fibromas?

1. enucleation and curettage

2. resection for recurrences

what are ameloblastic fibro-odontoma?

benign tumours made up of abnormal mixtures of cells and tissues {considered a "hamartoma"}

explain the clinical appearance of amelobastic fibro-odontomas

more likely to occur in the posterior regions of the jaw

asymptomatic and usually discovered by accident

associated with delayed/asymmetric tooth eruption

xray- well circumscribed, mixed radiolucencies and radiopacities

what are odontomas?

the most common benign tumours :

a hamartoma (abnormal collection of normal tissues)

2 main types- complex and compound

explain complex odontomas?

found in posterior mandible or maxilla

disorganised mass of enamel and dentin (no resemblance of tooth)

made up of irregular dentin and enamel masses

explain compound odontomas?

found in anterior maxilla

contains tiny tooth-like structures

xray- well defined, radiopaque, tooth resembling

what is an odontoameloblastoma?

very very rare benign tumour

what are the features of odontoameloblastoma?

locally aggressive

painless jaw expansion

explain the clinical appearance of odontoameloblastoma

xray- varying amount of radiopaque material- looks like displaced and unerupted teeth

what is the treatment for odontoameloblastoma?

surgical excision which includes 0.5-1cm healthy margins

what is an odontogenic fibroma? explain its clinical appearance

odontogenic epithelium embedded in fibrous storm

-> slow growing + painless

xray- radiolucent lesion -> unilocular or multilocular

causes cortical expansion/ tooth displacement

what is the treatment for odontogenic fibroma?

enucleation and curettage

what is an odontogenic myxoma?

rare, odontogenic, infiltrating tumour of the jaws

if left untreated it can spread to the base of the skull

what is a cementoblastoma?

odontogenic tumour of cementoblasts (tumour = fused to roots)

cause pain

xray- radiolucent ring surrounding a radiopaque lesion, around the roots of teeth

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