The document discusses various cysts that can occur in the oral and maxillofacial region. It begins by defining cysts and describing their general characteristics such as being fluid-filled cavities lined by epithelium and growing slowly by expansion. It then describes different types of cysts including true cysts lined by epithelium and pseudo cysts not lined by epithelium. The document further classifies cysts based on their location, discusses their pathogenesis, and provides details on specific cysts such as dentigerous cysts, odontogenic keratocysts, eruption cysts, and lateral periodontal cysts including their definitions, clinical features, radiographic appearances, histology, and complications.

1. Cysts Of The Oral
And
Maxillofacial Region

8. DEFINATION
• A Cyst is a pathological cavity having fluid, semifluid
or gaseous contents and which is not created by the
accumulation of pus. Most cysts, but not all, are lined
by epithelium. (KRAMER 1974).
• May occur within the bone or soft tissue
• Asymptomatic or associated with swelling and pain

9. • Cysts are generally slow growing, expansile lesions
• They grow by hydraulic expansion
• Radiographically, they often appear radiolucency
surrounded by thin radioopaque border
10

10. TYPESOF CYSTS
• TRUE CYSTS: that which is lined by epithelium e.g
dentigerous cyst, radicular cyst etc.
• PSEUDO CYSTS: not lined by epithelium, e.g. Solitary
bone cyst, Aneurismal bone cyst etc

11. PARTS OF A CYST
• Cyst has following parts:
• WALL (made of
connective tissue)
• EPITHELIAL LINING
• LUMEN OF CYST

12. CLASSIFICATION

13. I. Cysts of the jaws
1 Developmental Origin
a) Odontogenic
i. Gingival cyst of infants
ii. Odontogenic keratocyst
iii. Dentigerous cyst
iv. Eruption cyst
v. Gingival cyst of adults
vi. Developmental lateral
periodontal cyst
vii. Botryoid odontogenic cyst
viii. Glandular odontogenic cyst
ix. Calcifying odontogenic cyst
b) Non-odontogenic
i. Midpalatal raphé cyst of infants
ii. Nasopalatine duct cyst
iii. Nasolabial cyst
2 Inflammatory Origin
i. Radicular cyst, apical and lateral
ii. Residual cyst
iii. Paradental cyst and juvenile
paradental cyst
iv. Inflammatory collateral cyst
B. NON-EPITHELIAL-LINED CYSTS
1. Solitary bone cyst
2. Aneurysmal bone cyst
A. EPITHELIAL-LINED CYSTS

14. II. Cysts associated with the maxillary antrum
1. Mucocele
2. Retention cyst
3. Pseudocyst
4. Postoperative maxillary cyst

15. III. Cysts of the soft tissues of the mouth, face and
neck
1. Dermoid and epidermoid cysts
2. Lymphoepithelial (branchial) cyst
3. Thyroglossal duct cyst
4. Anterior median lingual cyst (intralingual cyst of foregut origin)
5. Oral cysts with gastric or intestinal epithelium (oral alimentary
tract cyst)
6. Cystic hygroma
7. Nasopharyngeal cyst
8. Thymic cyst
9. Cysts of the salivary glands: mucous extravasation cyst; mucous
retention cyst; ranula; polycystic (dysgenetic) disease of the
parotid
10. Parasitic cysts: hydatid cyst; Cysticercus cellulosae; trichinosis

16. PATHOGENESIS
• THREE STAGES
1. Cyst initiation
2. Formation
3. Cyst enlargement or
expansion
a. Initiation
b. Formation
c. Enlargement

17. CYST INITIATION
• Initiation results in the proliferation of the
epithelial cells and the formation of small cavity.
a. Cell Rests of Malassez :
Remanants of Hertwigs epithelial root sheath
b. Reduced Enamel Epithelium :
Residual epithelial cells surrounds the crown
of the tooth
c. Cell Rests of Serres (Dental Lamina) :
Islands of epithelial cells that originate from
the oral epithelium

18. CYST ENLARGEMENT
• Harris (1974) Postulated the theories
1) Mural growth
a) Peripheral cell division
b) Accumulated contents
2) Hydrostatic
a) Secretion
b) Transuduation & exudation
c) Dialysis

19. Mechanismregarding enlargement
1. Increase in the volume of its contents.
2. Increase in the surface area of the sac or epithelial
proliferation.
3. Resorption of surrounding bones.

20. Frequency of Epithelial Cysts of Jaws
52.30%
18.10%
11.60%
8%
5.60%
4.20% SHEAR 2006 Radicular cyst
Dentigerous cyst
Odontogenic keratocyst
Residual cyst
Paradental cyst
Unclassified odontogenic
cysts

21. DENTIGEROUS CYST

22. Definition: The dentigerous cyst is defined as a cyst that
originates by the separation of the follicle from around the
crown of an unerupted tooth
• The dentigerous cyst encloses the crown of an unerupted
tooth and is attached to the tooth at the cementoenamel
junction
• The pathogenesis of this cyst is uncertain, but apparently it
develops by accumulation of fluid between the reduced
enamel epithelium (REE) and the tooth crown.

23. Dentigerous cyst
Gross specimen of a dentigerous cyst.
Cyst encloses the crown of the tooth and is attached to its
neck

24. CLINICALFEATURES
• AGE : 1st to 3rd decades.
• GENDER : more frequently in males than in females.
• SITE :
• 2/3rd of follicular cyst associated with unerupted
mandibular teeth, primarily III molar.
• Maxillary canine
• Mandibular premolar
• Maxillary 3rd Molar
• Supernumerary tooth also can be involved

25. Signs & symptoms
• Most cysts grow to a large size before being discovered
accidentally while observing a dental x ray to detect the
cause of an unerupted tooth.
• Large lesions can cause cortical expansion, leading to facial
asymmetry, teeth displacement, root resorption, even pain,
if infected.

26. RADIOLOGICALFEATURES
• Manifests as unilocular, well defined, ‘lucency with
sclerotic margins, associated with crown of impacted /
unerupted tooth.
• A large DC may show persistence of bony trabeculae,
giving the appearance of multilocularity.

27. RADIOLOGICALFEATURES
• CENTRAL TYPE:
• LATERAL TYPE :
• CIRCUMFERENTIAL
TYPE :

28. Radiographic features
A central type of dentigerous cyst. Note resorption
of the root of the first mandibular molar

29. Radiographic features
Radiograph of two dentigerous cysts in the same patient. The cyst on the right is
a lateral type; that on the left is a circumferential type

30. HISTOLOGICALFEATURES
A. NON INFLAMMED TYPE:
• Lining derived from reduced dental epithelium, consists of
2-4 cell layers of non keratinized epithelium, without rete
ridges.
• Wall composed of thin fibrous connective tissue appearing
immature, as it is derived from the dental papilla.

31. NON INFLAMMED TYPE
NON INFLAMED dentigerous cyst shows a thin.
nonkeratinized epithelial lining.

32. HISTOLOGICALFEATURES
B. INFLAMED TYPE :
• Lining shows varying degrees of hyperplasia with rete
ridges and occasionally even keratinization.
• Wall is composed of mature connective tissue which
shows infiltration by chronic inflammatory cells.
• Focal areas of mucous cells can be seen in the lining.
Small odontogenic epithelial islands can be seen in the
wall.

33. INFLAMED TYPE
INFLAMED DENTIGEROUS CYST shows a thicker epithelial
lining with hyperplastic rete ridges. The fibrous cyst capsule shows a diffuse
chronic inflammatory infiltrate

34. DIFFERENTIAL DIAGNOSIS
Although it presents a unique feature, yet some lesions must be
considered in its differential diagnosis :
1. Unicystic ameloblastoma
2. Adenomatoid odontogenic tumor.

35. COMPLICATIONS
1. Recurrence due to incomplete surgical removal.
2. Development of ameloblastoma either from lining
epithelium or from odontogenic islands in the connective
tissue wall.
3. Development of squamous cell carcinoma from same two
sources.
4. Development of mucoepidermoid carcinoma from mucus
secreting cells in the lining.

36. ODONTOGENICKERATOCYST

37. • The odontogenic keratocyst is a distinctive form of
developmental odontogenic cyst that deserves special
consideration because of its specific histopathologic
features and clinical behavior.
• There is general agreement that the odontogenic
keratocyst arises from cell rests of the dental lamina.
• This cyst shows a different growth mechanism and
biologic behavior from the more common dentigerous
cyst and radicular cyst.

38. • Growth may be related to unknown factors inherent in
the epithelium itself or enzymatic activity in the fibrous
wall.
• Several investigators suggest that odontogenic
keratocysts be regarded as benign cystic neoplasms
rather than cysts
39

39. CLINICALFEATURES
• AGE : Wide age range 1st to 9th decade
• Peak frequency in the 2nd and 3rd decades.
• GENDER : more frequently in males than in females.
• SITE : The mandible > maxilla
• 50% cases occur in angle region and extend to
ascending ramus and forwards to body of mandible.

40. site diSTRIbuTION

41. CLINICALFEATURES
• Pain, swelling or discharge.
• Occasionally, paraesthesia of the lower lip or teeth.
• Develop pathological fractures.
• In many instances - free of symptoms until the cysts have
reached a large size, involving the maxillary sinus and the
entire ascending ramus, including the condylar and coronoid
processes.
• OKC tends to extend in the medullary cavity and clinically
observable expansion of the bone occurs late.

42. • GORLIN-GOLTZ syndrome, characterized by
• Multiple nevoid basal cell epitheliomas
• Odontogenic Keratocyst of the jaws
• Bifid ribs– sixth rib
• Plantar & palmar pits
• Occular hypertelorism
• Frontal bossing
• Ectopic calcifications

43. 44

44. RADIOGRAPHICFEATURES
• OKC demonstrate a well-defined radiolucent area with
smooth and often corticated margins.
• Large lesions, particularly in the posterior body and
ascending ramus of the mandible, may appear multilocular
• An unerupted tooth is involved in the lesion in 25% to 40%
of cases; in such instances, the radiographic features
suggest the diagnosis of dentigerous cyst

45. 46
Multilocular radiolucency
Unilocular radiolucency

46. Multiple okc
47

47. 48
1. REPLACEMENTAL –
Cyst forms in place of normal
tooth by degeneration of
dental lamina.
2. EXTRANEOUS –
OKC occurs in ascending
ramus, away from tooth
bearing areas
Radiographic variants of okc

48. 49
3. COLLATERAL –
OKC occurs adjacent to root of
tooth, mimicking a lateral
periodontal cyst.
4. ENVELOPMENTAL –
This is an odontogenic keratocyst
which embraces or envelopes an
adjacent unerupted tooth.

49. HISTOLOGICFEATURES
• Uniform layer of stratified squamous epithelium, usually 6-8
cells in thickness.
• Flat epithelium and connective tissue interface absence of rete
ridge.
• Basal cell layer has columnar / cuboidal cells with reversely
polarized nuclei, imparting a “picket fence” or “tombstone”
appearance.
• Luminal surface - flattened parakeratotic epithelial cells, which
exhibit a wavy or corrugated appearance.
• Small satellite cysts, cords, or islands of odontogenic epithelium
may be seen within the fibrous wall .

50. 51

51. 52
Parakeratinized OKC

52. 53
Orthokeratinized OKC

53. Satellite
microcysts
Satellite microcysts in the wall of an odontogenic keratocyst that
appear to be arising directly from an active dental lamina.

54. DIFFERENTIAL DIAGNOSIS
• In case of unilocular ‘lucencies – Dentigerous cyst,
Eruption cyst, COC, AOT, Unicystic ameloblastoma
etc.
• In case of multilocular ‘lucencies – Conventional
ameloblastoma, CEOT, Central giant cell granuloma,
Aneurysmal bone cyst etc.

55. • COMPLICATIONS IN OKC:
1. Malignant transformation of cyst lining rare, but has been
reported.
2. Recurrence – high rate of recurrence.
• REASONSFOR RECURRENCE :
1. Thin, fragile lining is very difficult to remove completely.
2. New cysts develop from satellite cysts left behind.
3. Some cysts may be left behind in cases of Gorlin – Gotz
syndrome.
4. New cysts can also develop from basal cells of overlying oral
epithelium, especially in ramus – 3rd molar region.

56. ERUPTIONCYST

57. ERUPTIONCYST
• Typical c/f of an eruption cyst. Note a bluish colored, dome
shaped swelling over the unerupted molar.
• The dentigerous cyst develops around the crown of an unerupted
tooth lying in the bone,
• The eruption cyst occurs when a tooth is impeded in its eruption
within the soft tissues overlying the bone.
Eruption cysts involving the
maxillary permanent incisors.

58. PATHOGENESIS
The circumscribed cavity contains blood
(due to surface trauma on biting with opposite
tooth )
It imparts purple / deep blue color
Hence known as
• ERUPTION HEMATOMA

59. CLINICALFEATURES
AGE : found in children of different ages, and occasionally
in adults if there is delayed eruption
SITE : most commonly associated with the first permanent
molars and the maxillary incisors

60. Radiological features
• The cyst may throw a soft-tissue shadow, but there is usually
no bone involvement except that the dilated and open crypt may
be seen on the radiograph.

61. HISTOLOGICALFEATURES
• Show surface oral epithelium on the
superior aspect. The underlying
lamina propria shows a variable
inflammatory cell infiltrate.
• The deep portion of the specimen,
which represents the roof of the
cyst, shows a thin layer at
nonkeratinizing squamous
epithelium
A cystic epithelial cavity can be seen
below the mucosal surface.

62. GINGIVALCYST OF ADULTS

63. pathogenesis
• A number of suggestions have been made about the
pathogenesis of the gingival cyst in adults.
• It was originally proposed that they may arise from
odontogenic epithelial cell rests; or by traumatic
implantation of surface epithelium; or by cystic
degeneration of deep projections of surface epithelium

64. origin
• Cystic transformation of dental lamina, traumatic
implantation of surface epithelium
• Dome shaped soft, fluctuant swelling which is <1cm in
diameter
• Lesion is slow growing and painless
• Adjacent teeth usually vital

65. Clinical features
• AGE : 5th – 6th decade of life
• SITE : mandibular canine and Pre Molar
area; attached gingiva or interdental papilla
• Signs and symptoms:
• Slowly enlarging, well circumscribed painless
swelling.
• Invariably occurs on facial aspect of free /
attached gingiva.
• Surface of lesion is smooth and of normal
color.

66. Radiological features
Radiograph of a gingival cyst in an adult. There is a faint radiographic
shadow (marked with arrows) indicative of superficial bone erosion.

67. Histology
• H/p features identical to Lateral periodontal cyst.
• Some cysts lined by thin, flattened stratified squamous
epithelium.
• Sometimes, focal thickenings (Plaques) may be found
within the lining.

68. LATERALPERIODONTALCYST

69. LATERALPERIODONTALCYST
• Uncommon, but well recognized type of odontogenic cyst.
• The designation ‘lateral periodontal cyst’ is confined to
those cysts that occur in the lateral periodontal position
and in which an inflammatory etiology and a diagnosis of
collateral OKC have been excluded on clinical and
histological grounds (Shear and Pindborg, 1975).

70. CLINICALFEATURES
• Age : 20 – 60 years, peak in 6th decade.
• Sex : Male predilection.
• Site : Lateral PDL regions of mandibular premolars,
followed by anterior maxilla

71. Signs & symptoms
• Usually asymptomatic as it occurs on the lateral aspect of
root of tooth.
• Occasionally pain and swelling may occur.
• Associated teeth are vital, unless otherwise affected.
• Cysts are < 1cm in size, except for BOTRYOID
VARIETY which is larger and also a multilocular lesion.

72. Radiological features
• Round to ovoid ‘lucency with sclerotic margins.
• Cyst can be present anywhere between cervical margin to
root apex.
• Radiographically, it can be confused with collateral OKC.

73. Radiological features
Lateral periodontal cyst. Radiolucent lesion
between the roots of a vital mandibular canine and
first premolar.
Lateral periodontal cyst. A larger lesion causing
root divergence.

74. HISTOLOGICALFEATURES
• The lateral periodontal cysts were lined by a thin, non-
keratinising layer of squamous or cuboidal epithelium
usually ranging from 1 to 5 cell layers wide, which resemble
the reduced enamel epithelium
• The epithelial cells were sometimes separated by
intercellular fluid. Their nuclei were small and pyknotic.
• Presence of what appear to be localised plaques or
thickenings of the epithelial lining
• Small epithelial nests may be seen in connective tissue wall,
which may show signs of mild inflammation.

75. HISTOLOGICALFEATURES
Lateral periodontal cyst which in part has a thin, nonkeratinised
stratified squamous epithelial lining resembling reduced enamel
epithelium. Two epithelial plaques are seen.

76. CALCIFYINGODONTOGENICCYST

77. CALCIFYINGODONTOGENICCYST
• Also called as Odontogenic ghost cell cyst or Gorlin cyst.
• It Has many features of odontogenic tumor, - placed in
the category of tumors in the latest WHO classification of
odontogenic cysts and tumors.
• In the latest WHO publication on odontogenic tumours
(Prætorius and Ledesma-Montes, 2005) it was classified
as a benign odontogenic tumour and was renamed
calcifying cystic odontogenic tumour (CCOT).

78. Clinical FeAtures
• Age : Wide range, peak in 2nd decade.
• Sex : Equal.
• Site : Anterior segment of both jaws

79. pathogenesis
• COC is a unicystic process and develops from the
reduced dental epithelium or remnants of dental
lamina.
• The cyst lining has the potential to induce formation of
dentinoid or even odontoma in adjacent CT wall.

80. CLASSIFICATION OF THE ODONTOGENIC GHOST
CELL LESIONS
• Group 1 : ‘Simple’ cysts Calcifying odontogenic cyst (COC)
• Group 2 : Cysts associated with odontogenic hamartomas or
benign neoplasms: calcifying cystic odontogenic tumours
(CCOT).
• Group 3 : Solid benign odontogenic neoplasms with similar
cell morphology to that in the COC, and with dentinoid
Formation
• Group 4 : Malignant odontogenic neoplasms with features
similar to those of the dentinogenic ghost cell tumour Ghost
cell odontogenic carcinoma

81. Signs & symptoms
• Swelling is the commonest complaint, seldom
associated with pain.
• Intraosseous lesions can cause hard bony expansion
and resulting facial asymmetry.
• Displacement of teeth can also occur.

82. RADIOLOGICALFEATURES
• Intraosseous lesions produce well
defined lucency which is usually
unilocular.
• Irregular calcified masses of varying
sizes may be seen within the lucency.
• Displacement of root/roots with or
without root resorption and
expansion of cortical plates also seen

83. Radiograph of a calcifying odontogenic cyst with well-demarcated
margins extending from the right to the left premolar regions of the
mandible. Numerous calcifications are present, some suggestive of
small denticles.

84. Histological features
• Lining is usually thin about 6 – 8 cell thick, may be
thickened in other areas.
• Lining shows characteristic odontogenic features with
reversely polarized basal cell layer.
• TYPICALLY – GHOST CELLS may be seen in thicker
areas of lining.
• Ghost cells are enlarged, ballooned, ovoid, eosinophilic cells
with well defined cell boundaries.
• Some times many cells may fuse.
• They represent abnormal keratinization and frequently
calcify.
• Tubular dentinoid and even complex odontome may be
found in connective tissue wall close to epithelial lining.

85. Histological features
Histological features of a calcifying odontogenic cyst with clusters of
fusiform ghost cells and focal calcifications, lying in a stratified squamous
epithelium.

86. Histological features
In this calcifying odontogenic cyst, there are sheets of ghost cells and a
focal area in which there has been induction of a strip of dysplastic
dentine (dentinoid).

87. DIFFERENTIAL DIAGNOSIS
• Based on radiographic appearance, following lesions
must be included in the provisional diagnosis –
• Ameloblastoma
• CEOT
• AOT
• Ameloblastic fibro odontoma

88. RADICULAR CYST

89. RADICULAR CYST
• Also called APICAL PERIODONTAL CYST
• Radicular cysts are the most common inflammatory
cysts and arise from the epithelial residues in the
periodontal ligament as a result of periapical
periodontitis following death and necrosis of the pulp.
• Quite often a radicular cyst remains behind in the jaws
after removal of the offending tooth and this is referred
to as a residual cyst.

90. PATHOGENESIS
1. PHASE OF INITIATION:
• Accepted generally that rests of Malassez included within
a developing periapical granuloma proliferates to form
the lining of radicular cyst.
• Some product of non vital pulp can be responsible which
simultaneously evokes an inflammatory response in CT.

91. 92

92. PATHOGENESIS
• 2. PHASE OF CYST FORMATION:
• Can occur in two possible ways.
• One theory states that epithelium proliferates and covers
the bare connective tissue surface of the abscess cavity.
• Another theory – cyst cavity forms within proliferating
epithelium as the cells in center move away from their
nutrient source.

93. 94

94. PATHOGENESIS
• 3. PHASE OF ENLARGEMENT:
• Enlargement occurs by collection of fluid within the
lumen of the cyst.
• Osmosis plays an important role here as the cyst wall
appears to have the properties of a semi permeable
membrane.

95. 96

96. CLINICALFEATURES
• Age : Peak in 3rd, 4th and 5th decades.
• Sex : Slightly more in males.
• Site : Maxillary anterior region.
• Frequency: Commonest cystic lesion of jaws.

97. Signs & symptoms
• Primarily symptom less.
• Discovered accidentally during routine dental X ray
exam.
• Slowly enlarging hard bony swelling initially.
• Diagnostic criteria – associated teeth are non vital
• Rare in deciduous teeth.

98. RADIOLOGICAL FEATURES
• Classically presents as round /
ovoid lucency with sclerotic
borders and associated with
pulpally affected tooth / teeth.
• If infection supervenes, the
margins become indistinct, making
it impossible to distinguish it from
a peripaical granuloma.

99. HISTOLOGICAL FEATURES
• Lined partly / completely by non keratinized
epithelium of varying thickness.
• Epithelium usually shows arcading around the
connective tissue.
• The connective tissue wall shows inflammatory
infiltrate mainly in the form of lymphocytes and
plasma cells.
• Hyaline / Rushton bodies are found in epithelium and
rarely in connective tissue wall.
• These are curved or linear structure with eosinophilic
staining properties

100. 101
Hyaline bodies in the epithelial lining
of a radicular cyst (H & E).

101. HISTOLOGICALFEATURES
• Cholesterol crystals in from of clefts are often seen in the
connective tissue wall, inciting a foreign body giant cell
reaction.
• Different types of dystrophic calcification are also seen in
connective tissue wall.
• Mucus cell metaplasia as well as respiratory cells may be
seen in the epithelial lining.
• Keratinization if found is due to metaplasia and must not
be confused with an OKC.

102. HISTOLOGICAL FEATURES
Quiescent epithelium lining a mature, long-standing
radicular cyst (H & E).
Mucous cells in the surface layer of the stratified
squamous epithelial lining of a radicular cyst (H & E).

103. HISTOLOGICAL FEATURES
Cholesterol clefts and multinuclear foreign body giant cells in a radicular cyst
(H& E).

104. 105

105. Residual cysts
• Radiographic appearance of a large residual
cyst left behind after extraction of 1st
mandibular molar.
• The histopathological features of
the residual cyst are similar to
conventional radicular cysts.
However, because the cause of
the cyst has been removed,
• Residual cysts may progressively
become less inflamed so that
eventually the cyst wall is
composed of uninflamed
• The epithelial lining may be thin
and regular and
indistinguishable from a
developmental cyst such as a
dentigerous cyst or lateral
periodontal cyst.

106. DIFFERENTIAL DIAGNOSIS:
• Following lesions must be distinguished from other
periapical radiolucencies–
1. Periapical granuloma
2. Peripaical cemento – osseous dysplasia (early lesions)

107. Paradental Cysts

108. Paradental Cysts
• A cyst of inflammatory origin-
occurring on lateral aspect of root
of partially erupted mandibular
3rd molar with an associated
history of pericoronitis
• Age : 20-40 years
• Tooth is vital
• Facial swelling
• Facial sinus in some cases

109. Radiographic features
• Affected tooth is tilted Well
demarcated RadioLucency
Distal to partially erupted
tooth
• Lamina Dura is intact
• New bone may be laid
down

110. Histological features
• The cysts are lined by a hyperplastic,
non keratinised, stratified squamous
epithelium which may be spongiotic
and of varying thickness.
• An intense inflammatory cell infiltrate
was present associated with the
hyperplastic epithelium
• fibrous capsule is the seat of an intense
chronic or mixed inflammatory cell
infiltrate.