Cysts Flashcards

1
Q

What is a cyst?

A

Pathological cavity containing fluid, semi-fluid or gas

Often lined by epithelium

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2
Q

What can the classification of a cyst be based on?

A

Location (jaw/soft tissues/maxillary antrum)

Cell type (epithelial/non-epithelial)

Pathogenesis (Developmental/inflammatory)

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3
Q

What are the 2 main categories of cysts based on WHO (1992)?

A

Epithelial

Non-epithelial

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4
Q

What are the 2 types of epithelial cysts?

A

Odontogenic & non-odontogenic

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5
Q

What are the 2 types of odontogenic cysts?

A

Inflammatory odontogenic cysts

Developmental odontogenic cysts

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6
Q

What are the 3 types of inflammatory odontogenic cysts?

A

Radicular cyst (apical & lateral)

Paradental cyst

Residual cyst

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7
Q

What are the 5 types of developmental odontogenic cysts?

A

Odontogenic keratocyst

Dentigerous cyst (Follicular/eruption cyst)

Lateral periodontal cyst

Glandular odontogenic cyst (sialo-odontogenic)

Gingival cyst of adults

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8
Q

Name 3 types of epithelial, non-odontogenic cysts

A

Median palatine cyst

Nasiolabial cyst

Nasopalatine cyst (incisive canal cyst)

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9
Q

Are non-epithelial cysts odontogenic or non-odontogenic?

A

Non-odontogenic

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10
Q

Name 2 types of non-epithelial cysts

A

Solitary bone cyst

Aneurysmal bone cyst

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11
Q

What are the 3 things needed for a cyst to form? (Pathogenesis)

A
  1. Source of epithelium
  2. Stimulus for cavitation + epithelial cell proliferation
  3. Mechanism(s) for continued cyst growth + accompanying bone resorption (cyst will only grow if bone is resorbed)
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12
Q

What is the source of epithelium of dentigerous cysts and how does it proliferate?

A

Reduced enamel epithelium (REE)

Space between REE + enamel leads to cyst formation

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13
Q

What are the 3 mechanisms of cyst growth?

A
  1. Internal hydraulic pressure
  2. Bone resorption
  3. Epithelial growth
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14
Q

Describe the internal hydraulic pressure mechanism of cystic growth and which cysts it occurs in

A

Expansion of inflammatory + dentigerous cysts

Protein accumulation within cyst walls as semipermeable membrane due to osmotic pressure

Fluid accumulates within cyst lumen creating positive pressure in the cysts -> encouraging bone resorption

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15
Q

Describe the bone resorption method of cystic growth

A

Pro-inflammatory cytokines IL-1 (released by macrophages), TNF + PGER (released by fibroblasts) induce bone resorption

Produced by inflammatory cells in cysts, stimulating bone resorption

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16
Q

What are the general clinical features of cysts?

A

Swelling

Displacement/loosening of teeth

Pain (if infected)

Eggshell cracking

Sign of fluctuance - movable/compressible; the larger the cycts, the more fluctuance

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17
Q

What type of radiograph would you take for small cystic lesions?

A

I/O PA

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18
Q

How many rads are usually taken for cysts? How are they taken and why?

A

2 images taken at right angles to each other

So can locate where the cyst is

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19
Q

Which radiographs are taken of the maxilla?

A

PA + oblique occlusal
OPG + lateral oblique
Occipitomental (OM)
True lateral
CBCT

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20
Q

Which radiographs are taken of the mandible?

A

PA + true occlusal
OPG + lateral oblique
PA (Ap) of mandible
CBCT

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21
Q

What are the radiological signs to look for?

A

Location
Size
Shape
Margin
Effect on adjacent structures

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22
Q

How do cysts appear clinically?

A

Well-defined, round or oval radiolucency

Well-defined margin

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23
Q

What type of teeth are radicular cysts related to?

A

Related to non-vital tooth

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24
Q

Where do radicular cysts develop within?

A

Periapical granuloma

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25
Describe how a radicular cyst would look on a radiograph
Unilocular, well defined, well corticated radiolucency at apex of non-vital tooth
26
Where is the commonest site of radicular cysts?
Upper incisors
27
What are the peak ages for a radicular cyst?
4-5th decade
28
Describe the nature of radicular cysts' growth
Regular growth limited buccal expansion Usually continuous with the lamina dura of root of affected tooth
29
Do radicular cysts cause resorption?
Do not usually cause resorption If long-standing can cause resorption + displacement of adjacent teeth
30
How are radicular cysts treated?
Endo surgical extraction
31
What can form if a radicular cyst is retained following an extraction?
Residual radicular cyst
32
Describe what a residual radicular cyst looks like on a radiograph
Well-defined, round/oval radiolucency
33
Where are residual radicular cysts always found?
Edentulous area After extraction of affected tooth
34
What is the key histology of a radicular cyst?
Thick wall of fibrous granulation tissue Inflamed - chronic + acute inflammatory cells (neutrophils) Cholestrol clefts + foreign body giant cells in wall/lumen Mucous cells particularly in maxillary cysts, due to location - hyaline bodies may be seen
35
Describe the epithelial lining of a radicular cyst
Non-keratinised stratified squamous Variable thickness most common but can be thin/attenuated in long-standing cysts
36
What is inside the lumen of a radicular cyst?
Pale pink serous exudate, macrophages, desquamated epithelial cells, inflammatory cells + cholestrol clefts
37
What are dentigerous cysts also known as?
Eruption cysts
38
What are dentigerous cysts attached to?
Attached at CEJ surrounding crown of unerupted 8s + 3s (typically enveloping crown)
39
What is the peak age for a dentigerous cyst?
3-4th decade
40
When is a cyst expected in regard to the follicular space?
If it exceeds 3mm
41
Describe the radiological appearance of a dentigerous cyst
Unilocular, well-corticated radiolucency, late buccal expansion Classically crown of associated tooth lies centrally within cyst
42
What is the treatment of a dentigerous cyst?
Surgical removal/uncover tooth
43
Do dentigerous cysts recur?
No recurrence
44
Describe the key histology of dentigerous cysts
Cyst wall variably thick often with a bluish myxoid appearance like dental follicle Pink exudate sometimes in cavity Mucous metaplasia common
45
Describe the epithelial lining of dentigerous cysts
Non-keratinised stratified squamous epithelium on a flat basement membrane 2-5 cells thick If inflamed lining looks like inflammatory cysts
46
What is found in the lumen of dentigerous cysts?
Pink serous exudate, cholestrol clefts
47
What is the commonest site of a odontogenic keratocyst?
Angle of mandible + ramus
48
Locularity of an odontogenic keratocyst?
Usually multilocular, but can be unilocular + associated with an unerupted tooth, very little expansion
49
What is the peak age of odontogenic keratocysts?
2nd + 3rd decades
50
How does an odontogenic keratocyst grow?
Through medullary bone with late buccal expansion May be associated with tooth root resorption
51
What is the treatment for odontogenic keratocysts?
Surgical removal
52
Does recurrence occur with odontogenic keratocysts + why?
Recurrence is common Due to difficulty in removal + daughter cysts
53
Multiple odontogenic keratocysts are associated with which syndrome?
Gorlin Goltz
54
What is another name for Gorlin Goltz syndrome?
Nevoid basal cell Carcinoma
55
What type of disease is Gorlin Goltz syndrome?
Rare autosomal disorder characterised by multiple basal cell carcinoma
56
List the clinical features of Gorlin Goltz syndrome
Developmental defects such as bifid ribs, spine + rib abnormalities Palmar + plantar epidermal pits Calcification of the falx cerebri Relative macrocephaly, facial milia, frontal bossing
57
Key histology of odontogenic keratocysts in someone with Gorlin Goltz syndrome
Thin fibrous cyst wall Normally uninflamed Small daughter cysts may be in the wall Epithelial lining is keratinised - normally parakeratinised with a corrugated surface - flat basement membrane Basal cells darkly stained with reversal of nuclear polarity - like ameloblasts Lumen filled with keratin
58
What is a lateral periodontal cyst?
Any cyst in the lateral periodontal region that is not an inflammatory cyst or an atypical odontogenic keratocyst
59
What are lateral periodontal cysts associated with?
Lateral roots of vital teeth
60
Describe the radiographic appearance of a lateral periodontal cyst
Usually very small, <1cm in diameter Round, well-defined, corticated + normally unilocular Can cause buccal expansion if very large
61
What is the key histology of a lateral periodontal cyst?
It is a developmental cyst so largely flat basement membrane Epithelial layer is 2-5 cells thick Thickened in areas to form swirled plaques Scattered glycogen rich clear cells May be multicystic Fibrous cyst wall is thin + uniformed
62
Where are nasopalatine cysts found?
Midline, anterior maxilla, just posterior to upper central incisors Associated with a vital maxillary incisor
63
At what age do nasopalatine cysts commonly form?
5-6th decade
64
Describe the radiological appearance of nasopalatine cysts
Well-defined, well-corticated monolocular radiolucency Round/oval
65
How big are nasopalatine cysts?
>6mm
66
What is the most common non-odontogenic cyst?
Nasopalatine cyst
67
Describe the key histology of nasopalatine cysts
Lining may be nonkeratinising stratified squamous or ciliated respiratory type epithelium, usually both Look for big nerves + blood vessels in wall
68
When are solitary bone cysts likely to form?
Children + adolescents under 20 years
69
Where are solitary bone cysts found?
Body of mandible
70
Describe the radiographic appearance of a solitary bone cyst
Well corticated, monolocular radiolucency Irregular outline
71
Describe the cavity of a solitary bone cyst
No wall/thin fibrous wall no epithelial lining Cyst lumen often empty
72
Describe the key histology of a solitary bone cyst
Fibrovascular tissue only No epithelial cyst lining Occasional giant cells + haemosidenin pigment may be seen
73
What is an aneurysmal bone cyst often classified as?
Giant cell lesion
74
At what age are aneurysmal bone cysts found?
Children + young adults
75
Describe the radiographic appearance of an aneurysmal bone cyst
Multilocular radiolucency in the mandible with cortical expansion
76
Describe what the aneurysmal cyst is like
Partially cystic partially solid Contains blood filled cystic spaces
77
Describe the key histology of the aneurysmal bone cyst
Localised proliferative lesion of vascular tissue, containing giant cells + granulation tissue therefore it is a soft tissue lesion
78
What are the 4 types of cysts in the soft tissues of the mouth, face + neck
Cysts of the salivary glands Lymphoepithelial (Branchial cleft) cyst Thyroglossal duct cysts Dermoid + Epidermoid cysts
79
Name 3 types of cysts of the salivary glands
Mucous extravasation cyst Mucous retention cyst Ranula
80
Where is the most common site of a mucous extravasation cyst?
Lower lip is quite common
81
Causes of mucous extravasation cysts
Related to trauma - e.g. pt biting on lip
82
What is the key histology of a mucous extravasation cyst?
Surrounded by granulation tissue
83
When are mucous retention cysts likely to happen?
In older age
84
Why do mucous retention cysts occur?
Dilated salivary duct filled mucin Related to ductal obstruction
85
When do lymphoepithelial (branchial) cleft cysts appear?
Late in childhood or in early adulthood
86
Describe the clinical appearance and location of a lympoepithelial (branchial cleft) cyst?
Presents as unilateral Soft tissue fluctuant swelling Typically appears in lateral aspect of neck, anterior to sternocleidomastoid muscle
87
What is the key histology of soft tissue cysts?
Look for an epithelial lining Look for mucin Look for a lymphoid stroma From epithelial remnants within lymphoid tissue Attenuated (reduced) epithelium surrounded by reactive lymphoid stroma
88
What are dermoid cysts?
Developmental anomalies occasionally in soft tissues of head + neck
89
Where are dermoid cysts found?
Entrapped epithelium normally in midline, floor of mouth above mylohyoid
90
What is the key histology of dermoid cysts?
Cyst lined by epidermis + skin
91
At what age are dermoid cysts found?
May be found at birth/in older patients Majority are 15 + 35 y/o F=M
92
How do thyroglossal cysts occur?
Developmental remnants of thyroglossal tract during descent of thyroid
93
Where do thyroglossal cysts occur?
In midline
94
What is the key histology of a thyroglossal cyst?
Cyst lined by attenuated/respiratory epithelium Often some thyroid follicles in the cyst wall
95
What are cholesterol clefts?
Spaces left by cholesterol crystals during tissue processing Cholesterol is derived from the breakdown of RBCs Clefts are a feature of inflamed cysts + are non-specific
96
Where do we see mucous metaplasia?
Can be seen in any cysts but common in dentigerous cysts + maxillary cysts
97
Where are hyaline bodies found + what are they?
Found in odontogenic cysts Only material secreted by odontogenic epithelium + similar to dental cuticle
98
Where do we see a flat basement membrane?
Normally associated with developmental odontogenic cysts -e.g. dentigerous + keratocysts
99
What are the 3 ways to investigate a cyst?
1. Clinically 2. Biopsy 3. Radiologically
100
What is assessed clinically when investigating a cyst?
Site + vital/non-vital Absent/unerupted tooth Swelling Eggshell cracking, fluctuation Displacement/loosening of teeth
101
What are the 3 types of biopsies?
Aspiration Excisional biopsy Incisional biopsy
102
When would you carry out aspiration?
Aneurysmal bone cyst - looking for a blood-hemangioma Pus Serous exudate Keratin either by smear onto cytology slide or estimation of soluble protein
103
When would you carry out an incisional biopsy?
When lesion extensive/reason to believe it is not a simple cyst e.g. dif radiolucencies at angle of mandible
104
When would you carry out an excisional biopsy?
When lesion is small + amenable for excision