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
Q

Describe how a radicular cyst would look on a radiograph

A

Unilocular, well defined, well corticated radiolucency at apex of non-vital tooth

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26
Q

Where is the commonest site of radicular cysts?

A

Upper incisors

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27
Q

What are the peak ages for a radicular cyst?

A

4-5th decade

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28
Q

Describe the nature of radicular cysts’ growth

A

Regular growth limited buccal expansion

Usually continuous with the lamina dura of root of affected tooth

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29
Q

Do radicular cysts cause resorption?

A

Do not usually cause resorption

If long-standing can cause resorption + displacement of adjacent teeth

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30
Q

How are radicular cysts treated?

A

Endo

surgical extraction

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31
Q

What can form if a radicular cyst is retained following an extraction?

A

Residual radicular cyst

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32
Q

Describe what a residual radicular cyst looks like on a radiograph

A

Well-defined, round/oval radiolucency

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33
Q

Where are residual radicular cysts always found?

A

Edentulous area

After extraction of affected tooth

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34
Q

What is the key histology of a radicular cyst?

A

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

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35
Q

Describe the epithelial lining of a radicular cyst

A

Non-keratinised stratified squamous

Variable thickness most common but can be thin/attenuated in long-standing cysts

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36
Q

What is inside the lumen of a radicular cyst?

A

Pale pink serous exudate, macrophages, desquamated epithelial cells, inflammatory cells + cholestrol clefts

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37
Q

What are dentigerous cysts also known as?

A

Eruption cysts

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38
Q

What are dentigerous cysts attached to?

A

Attached at CEJ surrounding crown of unerupted 8s + 3s (typically enveloping crown)

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39
Q

What is the peak age for a dentigerous cyst?

A

3-4th decade

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40
Q

When is a cyst expected in regard to the follicular space?

A

If it exceeds 3mm

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41
Q

Describe the radiological appearance of a dentigerous cyst

A

Unilocular, well-corticated radiolucency, late buccal expansion

Classically crown of associated tooth lies centrally within cyst

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42
Q

What is the treatment of a dentigerous cyst?

A

Surgical removal/uncover tooth

43
Q

Do dentigerous cysts recur?

A

No recurrence

44
Q

Describe the key histology of dentigerous cysts

A

Cyst wall variably thick often with a bluish myxoid appearance like dental follicle

Pink exudate sometimes in cavity

Mucous metaplasia common

45
Q

Describe the epithelial lining of dentigerous cysts

A

Non-keratinised stratified squamous epithelium on a flat basement membrane 2-5 cells thick

If inflamed lining looks like inflammatory cysts

46
Q

What is found in the lumen of dentigerous cysts?

A

Pink serous exudate, cholestrol clefts

47
Q

What is the commonest site of a odontogenic keratocyst?

A

Angle of mandible + ramus

48
Q

Locularity of an odontogenic keratocyst?

A

Usually multilocular, but can be unilocular + associated with an unerupted tooth, very little expansion

49
Q

What is the peak age of odontogenic keratocysts?

A

2nd + 3rd decades

50
Q

How does an odontogenic keratocyst grow?

A

Through medullary bone with late buccal expansion

May be associated with tooth root resorption

51
Q

What is the treatment for odontogenic keratocysts?

A

Surgical removal

52
Q

Does recurrence occur with odontogenic keratocysts + why?

A

Recurrence is common

Due to difficulty in removal + daughter cysts

53
Q

Multiple odontogenic keratocysts are associated with which syndrome?

A

Gorlin Goltz

54
Q

What is another name for Gorlin Goltz syndrome?

A

Nevoid basal cell Carcinoma

55
Q

What type of disease is Gorlin Goltz syndrome?

A

Rare autosomal disorder characterised by multiple basal cell carcinoma

56
Q

List the clinical features of Gorlin Goltz syndrome

A

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
Q

Key histology of odontogenic keratocysts in someone with Gorlin Goltz syndrome

A

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
Q

What is a lateral periodontal cyst?

A

Any cyst in the lateral periodontal region that is not an inflammatory cyst or an atypical odontogenic keratocyst

59
Q

What are lateral periodontal cysts associated with?

A

Lateral roots of vital teeth

60
Q

Describe the radiographic appearance of a lateral periodontal cyst

A

Usually very small, <1cm in diameter

Round, well-defined, corticated + normally unilocular

Can cause buccal expansion if very large

61
Q

What is the key histology of a lateral periodontal cyst?

A

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
Q

Where are nasopalatine cysts found?

A

Midline, anterior maxilla, just posterior to upper central incisors

Associated with a vital maxillary incisor

63
Q

At what age do nasopalatine cysts commonly form?

A

5-6th decade

64
Q

Describe the radiological appearance of nasopalatine cysts

A

Well-defined, well-corticated monolocular radiolucency

Round/oval

65
Q

How big are nasopalatine cysts?

A

> 6mm

66
Q

What is the most common non-odontogenic cyst?

A

Nasopalatine cyst

67
Q

Describe the key histology of nasopalatine cysts

A

Lining may be nonkeratinising stratified squamous or ciliated respiratory type epithelium, usually both

Look for big nerves + blood vessels in wall

68
Q

When are solitary bone cysts likely to form?

A

Children + adolescents under 20 years

69
Q

Where are solitary bone cysts found?

A

Body of mandible

70
Q

Describe the radiographic appearance of a solitary bone cyst

A

Well corticated, monolocular radiolucency

Irregular outline

71
Q

Describe the cavity of a solitary bone cyst

A

No wall/thin fibrous wall no epithelial lining

Cyst lumen often empty

72
Q

Describe the key histology of a solitary bone cyst

A

Fibrovascular tissue only

No epithelial cyst lining

Occasional giant cells + haemosidenin pigment may be seen

73
Q

What is an aneurysmal bone cyst often classified as?

A

Giant cell lesion

74
Q

At what age are aneurysmal bone cysts found?

A

Children + young adults

75
Q

Describe the radiographic appearance of an aneurysmal bone cyst

A

Multilocular radiolucency in the mandible with cortical expansion

76
Q

Describe what the aneurysmal cyst is like

A

Partially cystic partially solid

Contains blood filled cystic spaces

77
Q

Describe the key histology of the aneurysmal bone cyst

A

Localised proliferative lesion of vascular tissue, containing giant cells + granulation tissue therefore it is a soft tissue lesion

78
Q

What are the 4 types of cysts in the soft tissues of the mouth, face + neck

A

Cysts of the salivary glands

Lymphoepithelial (Branchial cleft) cyst

Thyroglossal duct cysts

Dermoid + Epidermoid cysts

79
Q

Name 3 types of cysts of the salivary glands

A

Mucous extravasation cyst

Mucous retention cyst

Ranula

80
Q

Where is the most common site of a mucous extravasation cyst?

A

Lower lip is quite common

81
Q

Causes of mucous extravasation cysts

A

Related to trauma - e.g. pt biting on lip

82
Q

What is the key histology of a mucous extravasation cyst?

A

Surrounded by granulation tissue

83
Q

When are mucous retention cysts likely to happen?

A

In older age

84
Q

Why do mucous retention cysts occur?

A

Dilated salivary duct filled mucin

Related to ductal obstruction

85
Q

When do lymphoepithelial (branchial) cleft cysts appear?

A

Late in childhood or in early adulthood

86
Q

Describe the clinical appearance and location of a lympoepithelial (branchial cleft) cyst?

A

Presents as unilateral

Soft tissue fluctuant swelling

Typically appears in lateral aspect of neck, anterior to sternocleidomastoid muscle

87
Q

What is the key histology of soft tissue cysts?

A

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
Q

What are dermoid cysts?

A

Developmental anomalies occasionally in soft tissues of head + neck

89
Q

Where are dermoid cysts found?

A

Entrapped epithelium normally in midline, floor of mouth above mylohyoid

90
Q

What is the key histology of dermoid cysts?

A

Cyst lined by epidermis + skin

91
Q

At what age are dermoid cysts found?

A

May be found at birth/in older patients

Majority are 15 + 35 y/o

F=M

92
Q

How do thyroglossal cysts occur?

A

Developmental remnants of thyroglossal tract during descent of thyroid

93
Q

Where do thyroglossal cysts occur?

A

In midline

94
Q

What is the key histology of a thyroglossal cyst?

A

Cyst lined by attenuated/respiratory epithelium

Often some thyroid follicles in the cyst wall

95
Q

What are cholesterol clefts?

A

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
Q

Where do we see mucous metaplasia?

A

Can be seen in any cysts but common in dentigerous cysts + maxillary cysts

97
Q

Where are hyaline bodies found + what are they?

A

Found in odontogenic cysts

Only material secreted by odontogenic epithelium + similar to dental cuticle

98
Q

Where do we see a flat basement membrane?

A

Normally associated with developmental odontogenic cysts -e.g. dentigerous + keratocysts

99
Q

What are the 3 ways to investigate a cyst?

A
  1. Clinically
  2. Biopsy
  3. Radiologically
100
Q

What is assessed clinically when investigating a cyst?

A

Site + vital/non-vital
Absent/unerupted tooth
Swelling
Eggshell cracking, fluctuation
Displacement/loosening of teeth

101
Q

What are the 3 types of biopsies?

A

Aspiration
Excisional biopsy
Incisional biopsy

102
Q

When would you carry out aspiration?

A

Aneurysmal bone cyst - looking for a blood-hemangioma

Pus

Serous exudate

Keratin either by smear onto cytology slide or estimation of soluble protein

103
Q

When would you carry out an incisional biopsy?

A

When lesion extensive/reason to believe it is not a simple cyst

e.g. dif radiolucencies at angle of mandible

104
Q

When would you carry out an excisional biopsy?

A

When lesion is small + amenable for excision