scr - os & histopathology - cysts Flashcards

1
Q

what is a cyst

A

pathological cavity containing fluid / semi fluid / gaseous contents - NOT created by accumulation of pus

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2
Q

WHO 2017 classification of cysts

A

epithelial / non epithelial
epithelial becomes odontogenic & non odontogenic
odontogenic becomes inflammatory & developmental

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3
Q

epithelial odontogenic inflammatory cysts (4)

A
  1. radicular cyst
  2. residual cyst
  3. paradental cyst
  4. mandibular bifurcation cyst
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4
Q

clinical criteria of radicular cyst

A

4th-5th decades
60% maxilla
lateral incisor region
NON VITAL TEETH
often asymptomatic
can produce alveolar bone expansion +/- discharge

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5
Q

radiographic criteria of radicular cyst

A

round / ovoid radiolucency at root apex
unilocular / well defined
uniform radiolucency
corticated margin continuous with lamina dura key

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6
Q

histopathologic criteria of radicular cyst

A

regular lining of non keratinised squamous epithelium that is often incomplete
deposits of cholesterol
vascular capsule
inflammatory infiltrate in capsule
CT capsule

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7
Q

fibroblasts in radicular cyst

A

spindle shaped cells found with fibrous connective tissue

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8
Q

neutrophils in radicular cyst

A

round cells with nuclei that are segmented into lobes of condensed chromatin connected by filaments

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9
Q

plasma cells in radicular cyst

A

ovoid cells with eccentric nucleus with chromatin clumps arranged like a cartwheel

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10
Q

cholesterol clefts

A

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)

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11
Q

hyaline / rushton bodies

A

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

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12
Q

cyst content from radicular cyst

A

watery straw coloured fluid

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13
Q

aetiology of radicular cyst

A

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

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14
Q

to differentiate between granuloma & cyst

A

> 1cm diameter = cyst
<1cm diameter = granuloma
but can only diagnose following being sent to lab

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15
Q

how does cyst expand

A

increase in osmotic pressure due to activation & proliferation of epithelial rests of malassez
& by cytokine mediated growth
often asymptomatic & slow growing with limited expansion

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16
Q

tx options for radicular cysts

A

non surgical endo; RCT
surgical endo; periradicular surgery
apicectomy
XLA
last 3 are if it remains symptomatic

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17
Q

paradental cyst

A

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

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18
Q

mandibular buccal bifurcation cysts

A

in children
usually buccal aspect of erupting FPM

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19
Q

developmental odontogenic cysts

A
  1. dentigerous cyst
  2. OKC
  3. lateral periodontal cyst
  4. gingival cysts
  5. calcifying odontogenic cyst
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20
Q

dentigerous cyst

A

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

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21
Q

clinical criteria of dentigerous cyst

A

M>F
2nd-3rd decade
asymptomatic
often incidental finding
tooth missing from arch

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22
Q

radiographic criteria of dentigerous cyst

A

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

23
Q

histopathological criteria

A

thin non keratinised
stratified squamous epithelium
no significant inflammation

24
Q

why is dentigerous cyst commonly lower 8s and upper 3s

A

they have the highest rate of impaction

25
Q

follicular size v dentigerous cyst

A

<2.5mm = follicle
>4.2mm = probable cyst
>10mm = definite cyst
asymmetrical radiolucency = cyst

26
Q

tx of dentigerous cyst

A
  1. XLA of u/e tooth
  2. enucleation
  3. marsupialisation
27
Q

variation of dentigerous cyst

A

eruption cyst
soft tissue variation
caused by lack of separation of follicle & enlargement around tooth
commonly primary incisors / FPMs in children

28
Q

OKC

A

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

29
Q

clinical criteria of OKC

A

M>F
wide age range
70-80% mandible
usually asymptomatic unless infected
if infected white line of corticated margin is lost

30
Q

radiographic criteria of OKC

A

oval
well defined
uniform radiolucency
uni or multilocular

31
Q

histopathological criteria of OKC

A

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

32
Q

to diagnose OKC

A

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

33
Q

tx of OKC

A
  1. enucleation
  2. marsupialisation
34
Q

if multiple OKCs

A

associated with basal cell naevus syndrome which inc:
- basal cell carcinoma
- skeletal abnormalities
- skin pigmentation
aka gorlin goltz syndrome

35
Q

lateral periodontal cyst

A

rare
associated with lateral surface of tooth root
commonly canine / premolar region
vital tooth
asymptomatic / incidental finding

36
Q

clinical criteria of lateral periodontal cyst

A

middle aged
may present with expansion
vital
mandible > maxilla

37
Q

radiographic criteria of lateral periodontal cyst

A

well demarcated radiolucency
attached to side of root

38
Q

histopathological criteria of lateral periodontal cyst

A

thin stratified squamous epithelium
similar to gingival cysts

39
Q

gingival cysts

A

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

40
Q

calcifying odontogenic cyst clinical criteria

A

usually <40yrs
75% intraosseous
mainly anterior to FPM
small usually 1-3cm diameter
shape variable
monolocular
adjacent teeth usually displaced +/- resorbed
bony expansion

41
Q

calcifying odontogenic cyst radiographic criteria

A

initially radiolucent
uni or mulitlocular
in more advanced stage contains variable calcified radiopaque material
rarely recur - benign course

42
Q

non odontogenic epithelial cysts

A

nasopalatine duct cyst

43
Q

NPD cyst clinical criteria

A

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

44
Q

NPD cyst radiographic criteria

A

well defined & corticated margin
round / ovoid / heart shaped (due to superimposition of anterior nasal spine) radiolucency
over roots of central incisors
sclerotic margin

45
Q

NPD cyst histopathological criteria

A

non keratinised stratified squamous with modified respiratory epithelium

46
Q

cyst v incisive fossa

A

<6mm = incisive fossa
6-10mm = monitor
>10mm = suspect cyst

47
Q

non epithelial jaw cysts

A

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

48
Q

mx of cysts

A

referral
initial consultation
radiographs
biopsy
diagnosis
txp & consent

49
Q

what can you not enucleate

A

ameloblastoma

50
Q

cyst enucleation

A

removal of entire cyst lining & contents useful for radicular / residual / dentigerous / OKC

51
Q

complications of enucleation (4)

A
  • damage to IAN
  • communication with maxillary sinus
  • pathological # of mandible
  • risk of recurrence
52
Q

marsupialisation

A

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

53
Q

+/- of marsupialisation

A

+ 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

54
Q

segmental resection

A

removal of cyst with margin of normal bone
mainly for ameloblastoma / sarcoma
normally require 2ndary procedure for reconstruction of defect