S2 - Odontogenic tumours Flashcards
Learning Objectives
Key signs to look out for which may indicate odontogenic tumours (4)
- vital teeth with PA RL
- vital teeth with root resorption
- displaced teeth
- bony expansion
Main things about benign lesions (3)
destructive (locally expand)
challenging to treat
recurrence
Are odontogenic cysts malignant?
they range in pathology from hamartomas to malignant
What is a hamartoma?
normal cells in wrong position/ordering
(very benign)
What does sclerosing mean?
to become more fibrous
What is an odontogenic tumour?
neoplastic growths originating (and histologically resemble) tissues that form teeth and periodontal tissues
Name the most 2 common odontogenic cysts?
- odontoma (aka KCOC)
- ameloblastoma
What is odontogenesis? What are ameloblasts and odontoblasts?
teeth form through invaginations from the epithelium
ameloblasts (labelled) help form enamel
odontoblasts form from inside line outer pulp - produce dentine and tertiary dentine
What is an odontoma? How does it look?
most common odontogenic tumour
benign, linked to tooth development
can tell it is of dental origin - well demarcated border, doesnt blend in with surrounding bone, pseudo-PDL walls off the cementum
Describe behaviour of lesion. What is this a common presentation of?
destroying cortex and expanding into buccal space
ameloblastoma - locally invasive
Most common multilocular radiolucency occuring in the jaws?
ameloblastoma
What is an ameloblastoma? Common presentation, symptoms, finding, associated tooth vitality, common site, behaviour?
- neoplasm arising from odontogenic epithelium, commonly presents as PAINLESS SWELLING
- uni or multilocular (soap bubble appearance)
- symptoms: painless asymptomatic
- incidental finding
- associated teeth: vital
- common site: often in posterior mandible
- behaviour: benign but aggressive and locally invasive and resorb bone, if untreated it grows and can cause pathological fracture
Histological features of ameloblastoma
- discrete islands which enclose central mass of cells that resemble stellate reticulum
- discrete islands of tumour (each thing)
- enclose loosely arranged polyhedral cells that resemble stellate reticulum
- solid/cystic -> degenration of SR
- peripheral cuboidal or columnar cells
What is an odontogenic keratocyst (OKC)?
- arise from seres cells rest of dental lamina
- rare and benign
- aggressive and locally invasive
- mainly posterior mandible
Describe lesion
distoangularly displaced 48 associated with well defined RL extending from there to there displacing the IAN
(OKC - cant say from just radiograph)
Describe histology of OKC and why they recur?
- parakeratinised squamous epithelium
- corrugated surface
- loss of rete pegs
- nuceli of basal layer of epithelium is palisaded
- very thin walls (only few cells thick, like wet tissue paper)
- epithelial rests stay deep within bone but making it recur and difficult to remove (as so thin)
Features of dentigerous cysts (5-6)
- associated with unerupted tooth, attached at CEJ
- contains fluid
- DOES NOT cause root resorption
- may displace teeth
- no neurological symptoms
- histology: non-keratinised stratified squamous epithelium (non-k SSE)
What is shown? What would indicate what this cyst is?
well-defined RL with scalloped edge, causing root resorption
teeth test vital, there is RR -> OKC
What is nerve sheath tumour
- very rare
- benign but locally expansive, very destructive
- causes dysaesthesia
- ill defined RL
