scr - os & histopathology - cysts Flashcards
what is a cyst
pathological cavity containing fluid / semi fluid / gaseous contents - NOT created by accumulation of pus
WHO 2017 classification of cysts
epithelial / non epithelial
epithelial becomes odontogenic & non odontogenic
odontogenic becomes inflammatory & developmental
epithelial odontogenic inflammatory cysts (4)
- radicular cyst
- residual cyst
- paradental cyst
- mandibular bifurcation cyst
clinical criteria of radicular cyst
4th-5th decades
60% maxilla
lateral incisor region
NON VITAL TEETH
often asymptomatic
can produce alveolar bone expansion +/- discharge
radiographic criteria of radicular cyst
round / ovoid radiolucency at root apex
unilocular / well defined
uniform radiolucency
corticated margin continuous with lamina dura key
histopathologic criteria of radicular cyst
regular lining of non keratinised squamous epithelium that is often incomplete
deposits of cholesterol
vascular capsule
inflammatory infiltrate in capsule
CT capsule
fibroblasts in radicular cyst
spindle shaped cells found with fibrous connective tissue
neutrophils in radicular cyst
round cells with nuclei that are segmented into lobes of condensed chromatin connected by filaments
plasma cells in radicular cyst
ovoid cells with eccentric nucleus with chromatin clumps arranged like a cartwheel
cholesterol clefts
derived from breakdown of RBCs as a result of haemorrhage
may be few in no or form large mural nodules
usually associated with epithelial discontinuities & project into cyst lumen
cholesterol crystals found in cyst fluid
cholesterol dissolves out during prep of section leaving clefts (looks like wavy white lines on stain)
hyaline / rushton bodies
translucent & pink staining lamellar bodies which are formed by cyst lining epithelium
eosinophilic bodies of varying size and shape of unknown origin that may represent some type of epithelial product
look like big pale splodges with dark outer staining
cyst content from radicular cyst
watery straw coloured fluid
aetiology of radicular cyst
inflammation from apical periodontitis following from pulp necrosis leading to proliferation of epithelium via rests of malassez (which are originally from hertwig’s epithelial root sheath in dental follicle) if these are not activated it will remain granuloma
cysts form by:
1. proliferating epithelium with central necrosis
OR
2. epithelium grows to surround an area of fluid
to differentiate between granuloma & cyst
> 1cm diameter = cyst
<1cm diameter = granuloma
but can only diagnose following being sent to lab
how does cyst expand
increase in osmotic pressure due to activation & proliferation of epithelial rests of malassez
& by cytokine mediated growth
often asymptomatic & slow growing with limited expansion
tx options for radicular cysts
non surgical endo; RCT
surgical endo; periradicular surgery
apicectomy
XLA
last 3 are if it remains symptomatic
paradental cyst
usually on lateral aspect of partially erupted vital teeth i.e. M3M where pericoronitis is inflammatory stimulus
related to neck or coronal 1/3 of tooth
tx =
SPM = enucleation
TPM = XLA
mandibular buccal bifurcation cysts
in children
usually buccal aspect of erupting FPM
developmental odontogenic cysts
- dentigerous cyst
- OKC
- lateral periodontal cyst
- gingival cysts
- calcifying odontogenic cyst
dentigerous cyst
associated with crown of u/e usually impacted tooth
commonly M3M
occurs when fluid accumulated between crown & reduced enamel epithelium (from enamel organ) dilating tooth follicle & preventing eruption
cyst attached to ACJ of u/e tooth
clinical criteria of dentigerous cyst
M>F
2nd-3rd decade
asymptomatic
often incidental finding
tooth missing from arch
radiographic criteria of dentigerous cyst
round / ovoid
well defined unilocular / uniform radiolucency
corticated margins
attached at ADJ of tooth
larger cysts may envelope root of tooth
expand symmetrically initially but larger may expand unilaterally
histopathological criteria
thin non keratinised
stratified squamous epithelium
no significant inflammation
why is dentigerous cyst commonly lower 8s and upper 3s
they have the highest rate of impaction
follicular size v dentigerous cyst
<2.5mm = follicle
>4.2mm = probable cyst
>10mm = definite cyst
asymmetrical radiolucency = cyst
tx of dentigerous cyst
- XLA of u/e tooth
- enucleation
- marsupialisation
variation of dentigerous cyst
eruption cyst
soft tissue variation
caused by lack of separation of follicle & enlargement around tooth
commonly primary incisors / FPMs in children
OKC
3rd most common after radicular & dentigerous
originates from tooth structure but no specific relationship to teeth
arises from cell rests of serres which originates from remnants of dental lamina
clinical criteria of OKC
M>F
wide age range
70-80% mandible
usually asymptomatic unless infected
if infected white line of corticated margin is lost
radiographic criteria of OKC
oval
well defined
uniform radiolucency
uni or multilocular
histopathological criteria of OKC
thin CT wall
uninflamed
thin parakeratinised stratified squamous epithelium
no RETE PEGS with epithelium & CT
pallisading of basal cell nuclei
presence of daughter / satellite cells due epithelium being able to separate from wall following surgery leads to high recurrence rate - look like big pink / purple dots
to diagnose OKC
aspiration biopsy
thick grey / white cheesy material with keratinous debris
should contain squames & low soluble protein content (<4g/dl)
squame = superficial keratinised squamous cell generally anucleated & increased no indicates abnormal keratinisation
tx of OKC
- enucleation
- marsupialisation
if multiple OKCs
associated with basal cell naevus syndrome which inc:
- basal cell carcinoma
- skeletal abnormalities
- skin pigmentation
aka gorlin goltz syndrome
lateral periodontal cyst
rare
associated with lateral surface of tooth root
commonly canine / premolar region
vital tooth
asymptomatic / incidental finding
clinical criteria of lateral periodontal cyst
middle aged
may present with expansion
vital
mandible > maxilla
radiographic criteria of lateral periodontal cyst
well demarcated radiolucency
attached to side of root
histopathological criteria of lateral periodontal cyst
thin stratified squamous epithelium
similar to gingival cysts
gingival cysts
derived from remnants of dental lamina i.e. rests of serres in gingival / alveolar soft tissues
in adults = <1cm pink / blue sessile swellings
in children = bohn’s nodules (similar to epstein pearls which are on palate but aren’t odontogenic) naturally degenerate
calcifying odontogenic cyst clinical criteria
usually <40yrs
75% intraosseous
mainly anterior to FPM
small usually 1-3cm diameter
shape variable
monolocular
adjacent teeth usually displaced +/- resorbed
bony expansion
calcifying odontogenic cyst radiographic criteria
initially radiolucent
uni or mulitlocular
in more advanced stage contains variable calcified radiopaque material
rarely recur - benign course
non odontogenic epithelial cysts
nasopalatine duct cyst
NPD cyst clinical criteria
M>F
5th-6th decades
often asymptomatic
may have salty taste & vital teeth i.e. no infection
slowly enlarging swelling anterior midline of palate
always involves midline
but not always symmetrical
larger cysts can displace teeth
NPD cyst radiographic criteria
well defined & corticated margin
round / ovoid / heart shaped (due to superimposition of anterior nasal spine) radiolucency
over roots of central incisors
sclerotic margin
NPD cyst histopathological criteria
non keratinised stratified squamous with modified respiratory epithelium
cyst v incisive fossa
<6mm = incisive fossa
6-10mm = monitor
>10mm = suspect cyst
non epithelial jaw cysts
solitary bone cyst - asymptomatic, incidental, aetiology unknown
aneurysmal bone cyst - blood aspirated into this during biopsy
stafne’s idiopathic bone cavity - not a cyst just a depression / concavity in bone, only occurs in mandible
mx of cysts
referral
initial consultation
radiographs
biopsy
diagnosis
txp & consent
what can you not enucleate
ameloblastoma
cyst enucleation
removal of entire cyst lining & contents useful for radicular / residual / dentigerous / OKC
complications of enucleation (4)
- damage to IAN
- communication with maxillary sinus
- pathological # of mandible
- risk of recurrence
marsupialisation
creation of surgical window in wall of cyst to remove contents & suture surrounding epithelium
encourages cyst to decrease in size for later enucleation (can take 1yr)
tube / grommit insertion
useful for large cyst
+/- of marsupialisation
+ simple
+ may spare vital structures
+ later enucleation
- opening may close
- long tx prior to completion
- complete lining unavailable for histopathology
- difficult to keep clean & a lot of aftercare required
- chance of reinfection
- uncomfortable
segmental resection
removal of cyst with margin of normal bone
mainly for ameloblastoma / sarcoma
normally require 2ndary procedure for reconstruction of defect
