1. The document discusses various cysts that can occur in the oral and maxillofacial region, classifying them as either epithelial-lined cysts or non-epithelial lined cysts and further dividing them based on anatomical location and origin. 2. Key cysts discussed in detail include dentigerous cysts, odontogenic keratocysts, and eruption cysts. Dentigerous cysts form around the crowns of unerupted teeth, odontogenic keratocysts have a higher recurrence rate than other cysts, and eruption cysts are blood-filled swellings associated with delayed tooth eruption. 3. Radiographic, hist

1. Good Afternoon....
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2. 2

3. Cysts Of The Oral And
Maxillofacial Region
Presented by,
Dr Ravikumar V,
Dept Of Oral Pathology,
Govt Dental College,
Kottyam

4. Brushing up…
• Definition
• True cysts and pseudocysts

5. CLASSIFICATION

6. I. Cysts of the jaws
A. EPITHELIAL-LINED CYSTS
1. Developmental Origin
• (a) Odontogenic
i.
ii.
iii.
iv.
v.
vi.
Gingival cyst of infants
Odontogenic keratocyst
Dentigerous cyst
Eruption cyst
Gingival cyst of adults
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

7. I. Cysts of the jaws
2 .INFLAMMATORY ORIGIN
i.
ii.
iii.
iv.
Radicular cyst, apical and lateral
Residual cyst
Paradental cyst and juvenile paradental cyst
Inflammatory collateral cyst
• B. NON-EPITHELIAL-LINED CYSTS
1. Solitary bone cyst
2. Aneurysmal bone cyst

8. II. Cysts of the soft tissues of the mouth,
face and neck
1.
2.
3.
4.
5.
6.
7.
8.
9.
Dermoid and epidermoid cysts
Lymphoepithelial (branchial) cyst
Thyroglossal duct cyst
Anterior median lingual cyst (intralingual cyst of foregut origin)
Oral cysts with gastric or intestinal epithelium (oral alimentary tract cyst)
Cystic hygroma
Nasopharyngeal cyst
Thymic cyst
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

9. PATHOGENESIS
•
TWO STAGES
1. Cyst initiation
2. Cyst enlargement or
expansion
a. Initiation
b. Formation
c. Enlargement

10. 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 in the PDL after the root formation is
completed.
b. Reduced Enamel Epithelium : Residual epithelial cells
surrounds the crown of the tooth after enamel formation is
complete.
c. Cell Rests of Serres (Dental Lamina) : Islands of epithelial
cells that originate from the oral epithelium and remain in
the tissue after inducing tooth development.

11. c
b
a
11

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

13. DENTIGEROUS
CYST

14. • 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
• It develops by accumulation of fluid between the reduced
enamel epithelium and the tooth crown.

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

16. CLINICAL FEATURES
•
•
•
•
•
•
•
•
AGE :
1st to 3rd decades.
GENDER : more frequently in males than in females.
SITE :
2/3rd associated with unerupted mandibular 3rd molar
Maxillary canine
Mandibular premolar
Maxillary 3rd Molar
Supernumerary tooth also can be involved

17. 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.

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

19. RADIOLOGICAL FEATURES
•
CENTRAL TYPE:
•
LATERAL TYPE :
•
CIRCUMFERENTIAL
TYPE :

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

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

22. HISTOLOGICAL FEATURES
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.

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

24. HISTOLOGICAL FEATURES
A. 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.

25. 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.

26. COMPLICATIONS
1.
2.
3.
4.
Recurrence
Development of
ameloblastoma.
Development of
squamous cell
carcinoma.
Development of
mucoepidermoid
carcinoma from mucus
secreting cells in the
lining.

27. ODONTOGENIC KERATOCYST / KCOT..???

28. • OKC’s arises from cell rests of the dental lamina.
• Have a different growth mechanism and biologic behavior from
the more common dentigerous cyst and radicular cyst.
• Several investigators suggest that odontogenic keratocysts be
regarded as benign cystic neoplasms rather than cysts

29. CLINICAL FEATURES
• AGE :
In most series there has been a pronounced
frequency in the second and third decades.
• GENDER :
more in males than in females.
• SITE :
The mandible is involved far more frequently
• 50% cases occur in angle region and extend to
ascending ramus and forwards to body of
mandible.

30. siTE diSTRIbuTION
Relative distribution of
odontogenic keratocysts in the jaws.

31. CLINICAL FEATURES
• Pain, swelling or discharge.
• Occasionally, paraesthesia of the lower lip or teeth.
• Some are unaware of the lesions until they develop
pathological fractures.
• In many instances, patients are remarkably 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.
• occurs because the OKC tends to extend in the medullary
cavity and clinically observable expansion of the bone occurs
late.

32. • 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

33. RADIOGRAPHIC FEATURES
• 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

34. RADIOGRAPHIC FEATURES
Radiograph of a small odontogenic keratocyst.

35. RADIOGRAPHIC FEATURES
Radiograph of an odontogenic keratocyst with scalloped
margins.

36. RADIOGRAPHIC FEATURES
Radiograph of a multilocular odontogenic keratocyst.

37. RADIOGRAPHIC FEATURES
Radiograph of an odontogenic keratocyst that has
enveloped an unerupted tooth to produce a ‘dentigerous’
appearance.

38. HISTOLOGIC FEATURES
• The epithelial lining is composed of a uniform layer of stratified
squamous epithelium,usually six to eight cells in thickness.
• The epithelium and connective tissue interface is usually flat, and
rete ridge formation is inconspicuous.
• The basal cell layer has columnar / cuboidal cells with reversely
polarized nuclei, imparting a “picket fence” or “tombstone”
appearance.
• The luminal surface shows 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 .

39. okc
Epithelial lining is 6 to 8 cells thick, with a hyperchromatic and
palisaded basal cell layer. Note the corrugated parakeratotic
surface.

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

41. 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.

42. • COMPLICATIONS IN OKC :
1. Malignant transformation of cyst lining rare, but has
been reported.
2. Recurrence – high rate of recurrence.
• REASONS FOR 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.

43. ERUPTION CYST

44. ERUPTION CYST
• 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.

45. 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

46. CLINICAL FEATURES
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

47. 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.

48. HISTOLOGICAL FEATURES
• 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
of nonkeratinizing squamous
epithelium
A cystic epithelial cavity can be seen below
the mucosal surface.

49. GINGIVAL CYST OF ADULTS

50. 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

51. Clinical features
AGE : 5th – 6th decade of life
SITE : mand. canine and Pre Molar
area; attached gingiva or I/D 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.
• Fluctuant lesion, adjacent
teeth are vital
Clinical photograph of a gingival cyst of an adult

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

53. Histology
• H/p features identical to
Lateral periodontal cyst.
G
J
• Some cysts lined by
thin, flattened stratified
squamous epithelium.
J
The epithelial lining of a gingival cyst of
the adult (G) lying contiguous to the
junctional epithelium (J) of an adjacent
tooth.
• Sometimes, focal
thickenings (Plaques) may
be found within the lining.

54. Narrow epithelial lining of a gingival cyst of the
adult. It resembles the reduced enamel
epithelium found in dentigerous
cysts.
Low-power photomicrograph of a
gingival cyst of the adult,
showing a very narrow epithelial cyst lining
(bottom) deep to the gingival epithelium.
54

55. LATERAL PERIODONTAL
CYST

56. LATERAL PERIODONTAL CYST
• 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).

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

58. 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 rarely > 1cm in size, except for BOTRYOID VARIETY which
is larger and also a multilocular lesion.

59. 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.
Radiograph of a lateral periodontal cyst lying between the
mandibular premolar teeth. The margins are well
corticated, indicative of slow enlargement.

60. 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.

61. HISTOLOGICAL FEATURES
Lateral periodontal cyst which in part has a
thin, nonkeratinised stratified squamous epithelial lining
resembling reduced enamel epithelium. Two epithelial plaques
are seen. The one on the right is convoluted

62. HISTOLOGICAL FEATURES
• The lateral periodontal cysts were lined by a thin, nonkeratinising layer of squamous or cuboidal epithelium usually
ranging from 1 to 5 cell layers wide, which resembled the
reduced enamel epithelium
• The epithelial cells were sometimes separated by intercellular
fluid. Their nuclei were small and pyknotic.
• An interesting feature seen in many of the lateral periodontal
cysts was the 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.

63. Diagram illustrating the possible mode of formation of epithelial plaques by localised proliferation of cells.
(a) Cyst lined by thin epithelium resembling reduced enamel epithelium. (b) Early epithelial thickening by basal cell
proliferation. (c) Basal cells continue to proliferate. Superficial cells swell by accumulation of intracellular fluid. (d) and (e)
Basal proliferation ceases or slows down. Superficial cells are waterlogged and swollen. Plaque protrudes into cyst cavity
and cyst wall where it can undermine and raise adjacent cyst lining. (f) Epithelial plaque can form convolutions. Protrusions
into cyst wall as in (c–f) may be ‘pinched off’ and develop into daughter cysts, leading to the formation of the botryoid
variety of lateral periodontal cyst.

64. 64

65. CALCIFYING ODONTOGENIC
CYST
• Also called as Odontogenic ghost cell cyst or Gorlin cyst.
• 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).

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

67. Classification and 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.

68. 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.

69. RADIOLOGICAL FEATURES
•
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
Radiograph of a calcifying odontogenic cyst of the maxilla.
There is a well-demarcated margin and calcifications
suggestive of tooth material.

70. RADIOLOGICAL FEATURES
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.

71. 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.

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

73. 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).

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

75. Nasopalatine duct Cyst / Incisive canal
cyst
75

76. Nasopalatine Duct
(Incisive Canal) Cyst
• Also classified as “FISSURAL CYSTS”.
• Believed to be derived from epithelial remnants included
during closure of embryonic facial processes.
• Controversy – actual “closure” of embryonic processes does
not occur. Grooves between processes is smoothed by
proliferation of underlying mesenchyme.
• Usually occurs within the nasopalatine canal or in soft tissue
of palate at the opening of canal.

77. CLINICAL FEATURES
• Age :
• Sex :
4th, 5th & 6th decades.
More in females
• Frequency: Commonest non odontogenic
developmental cyst

78. PATHOGENESIS
• In lower animals, the NP duct concerned with olfactory
sensation – in humans only vestigial remnants persist in
incisive canal in form of epithelial islands, ducts, cords etc.
• These nests can show central degenration to form cysts.
Etiology for cyst transformation is yet unclear.
• Some believe, it may arise spontaneously like an OKC.

79. Signs & symptoms
• Commonest symptom is
swelling, usually in anterior
region of mid palate.
• Swelling can also occur in midline
on labial aspect of alveolar ridge.
• If pressure on NP nerves – pain
• Exclude possibility of periapical
cyst by testing vitality of incisors.

80. Nasopalatine Duct
(Incisive Canal) Cyst
Small nasopalatine cyst presenting as a soft ovoid
swelling in the midline of the maxilla, posterior to
the central incisor teeth.
Large nasopalatine duct cyst extending laterally and
posteriorly to involve much of the hard palate.

81. RADIOLOGICAL FEATURES
• Seen as lucency usually in
incisive canal – DIFFICULT TO
DISTINGUISH FROM A NATURALLY
LARGE INCISIVE CANAL.
• Lucency with AP dimension upto
10 mm considered as enlarged
incisive canal, but if lucency < 14
mm, then NP duct cyst.
• The lucency appears well defined
with sclerotic borders, in midline
of palate between roots of
incisors.

82. RADIOLOGICAL
FEATURES
Radiograph of a nasopalatine
duct cyst showing a pear-shaped
radiolucency in the anterior maxilla.
The lamina dura on the left is intact
although the apex appears
to be in the cyst.

83. Histological features
• Lining epithelium extremely
variable, consisting of
stratified squamous, pseudo
stratified columnar, simple
columnar or cuboidal
epithelium.
• Most commonly lining is
stratified squamous followed
by pseudo stratified columnar.
• A useful diagnostic aid –
presence of large nerve and
vascular bundles in connective
tissue wall.

84. Histological features
Neurovascular bundle in the wall of a
nasopalatine duct cyst.

85. DIFFERENTIAL DIAGNOSIS
• Radicular cyst, if it is associated with a pulpally involved tooth.
• Large incisive canal.

86. NASOLABIAL CYST

87. NASOLABIAL CYST
•
The nasolabial cyst occurs outside the bone in the nasolabial
folds below the alae nasi.
•
It is traditionally regarded as a jaw cyst although strictly
speaking it should be classified as a soft tissue cyst.

88. Clinical features
• Age :
Peak incidence in 4th & 5th decades.
• Sex :
More in females.
• Frequency: Rare in occurrence.

89. Signs & symptoms
• Commonest complaint –
slowly growing swelling and
occasionally, pain and
difficulty in nasal breathing.
• Extra orally – filling out of
nasolabial fold and may lift
ala nasi.
• Intra orally – bulge in labial
sulcus.
• Fluctuant lesion.
Nasolabial cyst producing a swelling of the right
upper lip, forming a bulge in the labial sulcus.

90. PATHOGENESIS
• Believed to develop from lower anterior portion of nasolacrimal
duct.
• When margins of lateral and maxillary processes fuse, ectoderm
along boundary between them gives rise to solid cellular rod
which first develops as a linear surface elevation (Nasolacrimal
ridge) and then sinks into underlying mesenchyme.
• This solid rod canalizes to form NL duct.
• The NL cysts are located such that it is possible that they
develop from embryonic remnants of NL duct.
• Importantly, a mature NL duct is lined by pseudo stratified
columnar epithelium, which is also the lining of NL cyst.

91. RADIOLOGICAL FEATURES
• Difficult to interpret on
radiograph.
• May be seen as localized
increased lucency of
alveolar process above
apices of incisors.
• Lucency results from
pressure resorption on
labial surface of maxilla.
Standard occlusal radiograph of a patient with a nasolabial
cyst. There is a posterior convexity of the left half of the
radiopaque line that forms the bony border of the nasal
aperture.

92. HISTOLOGICAL FEATURES
• Cyst lined by non ciliated pseudo
stratified columnar epithelium.
• Goblet cells also seen in some
cases.
• Occasionally, part of lining may
be cuboidal / flat squamous.
• Conncetive tissue wall is
fibrous, relatively acellular with
fibers arranged loosely or
compactly.
Nasolabial cyst lined by a pseudostratified
columnar epithelium containing many goblet cells.
In the example illustrated here, mucous glands are
present in the wall.

93. RADICULAR CYST

94. 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.

95. CLINICAL FEATURES
• Age :
peak in 3rd, 4th and 5th decades.
• Sex :
Slightly more in males.
• Site :
Maxillary anterior region.
• Frequency: Commonest cystic lesion of jaws.

96. Signs & symptoms
• Primarily symptom less.
• Discovered accidentally during routine dental X ray exam.
• Slowly enlarging hard bony swelling initially. Later, if cysts
breaks through cortical plates, lesion becomes fluctuant.
• Diagnostic criteria – associated teeth are non vital
• Rare in deciduous teeth.

97. 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.
Radiograph of a radicular cyst. The lesion is a well
defined radiolucency associated with the apex of a nonvital root filled tooth.

98. 98

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. HISTOLOGICAL FEATURES
• Cholesterol crystals in from of clefts are often seen in the
connective tissue wall, inciting a foreign body giant cell
reaction.
• Originate from disintegrating RBC’s in presence of
inflammation.
• 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.

101. 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).

102. HISTOLOGICAL FEATURES
Hyaline bodies in the epithelial lining of a radicular
cyst (H & E).
Mural nodule of cholesterol-containing granulation
tissue fungating into the cavity of a radicular cyst
(H & E).

103. Residual Cysts
103

104. Residual cysts
• The histopathological features of the
residual cyst are similar to those
described above for 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
•
Radiographic appearance of a large residual
cyst left behind after extraction of 1st
mandibular molar.
• The epithelial lining may be thin and
regular and indistinguishable from a
developmental cyst such as a
dentigerous cyst or lateral periodontal
cyst.

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

106. Paradental Cysts

107. Paradental Cysts
• A cyst of inflammatory originoccurring 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

108. Radiographic features
• Affected tooth is tilted
• Well demarcated
RadioLucency distal to
partially erupted tooth
• Lamina Dura is intact
• New bone may be laid
down
(a,b) Two cases of bilateral paradental cysts associated with erupting
mandibular third molar teeth. The cysts are distal and buccal to the
involved teeth. Note that the periodontal ligament space is not widened
and that the distal part of the cyst is separate from the distinct distal
follicular space.

109. Histological features
•
The cysts are lined by a
hyperplastic, nonkeratinised, stratified squamous
epithelium which may be spongiotic
and of varying thickness.
•
An intense inflammatory cell
infiltrate was present associated with
the hyperplastic epithelium and in
the adjacent fibrous capsule is the
seat of an intense chronic or mixed
inflammatory cell infiltrate. fibrous
capsule
Paradental cyst adjacent to the root of an impacted
mandibular third molar. The cyst is lined by non-keratinised
stratified squamous epithelium of variable thickness and
showing areas of proliferation (H & E).

110. Aneurysmal Bone Cyst

111. Aneurysmal Bone Cyst
• Uncommon cyst, found mostly in long bones and spine.
• CLINICAL FEATURES: 1. Age : First 3 decades.
2. Sex : Mainly females.
3. Site : molar regions of mandible & maxilla.
•
•
•
Signs & symptoms:
Hard, rapidly growing swelling which can cause malocclusion.
If lesion perforates cortical plates, can cause “egg shell
crackling”.

112. PATHOGENESIS
• Controversy whether lesion arises de novo or from a vascular
disturbance in the form of sudden venous occlusion or
development of an AV shunt occurring secondarily in a pre
existing lesion like central giant cell granuloma, Osteosarcoma
etc.
• Due to the malformation, change in hemodynamic forces
occurs which can lead to ABC.

113. RADIOLOGICAL FEATURES
• Classically seen as a unilocular, ovoid / fusiform lucency which
balloons the cortical plates.
• Teeth displacement and root resorption also observed.
• Lesions are usually unilocular but longer-standing lesions may
show a ‘soap-bubble’ appearance and may become
progressively calcified

114. Radiograph of an aneurysmal bone cyst involving the angle and
ascending ramus of the mandible. There is a ballooning expansion
of the cortex.

115. Histological features
• It consist of many capillaries and blood-filled spaces of varying size
lined by flat spindle cells and separated by delicate loose-textured
fibrous tissue
• Most lesions contain small multinucleate cells and scattered
trabeculae of osteoid and woven bone.
• In some of the solid areas, sheets of vascular tissue, containing
large numbers of multinucleate giant
cells, fibroblasts, haemorrhage and haemosiderin, look very much
like giant cell granuloma of the jaws
• The diagnosis is made primarily on the basis of the clinical and
radiological features because histologically such solid lesions may
be indistinguishable from giant cell granuloma.

116. Histological features
Aneurysmal bone cyst in which the solid areas have
histological features identical to those of the central
giant cell granuloma of the jaws (H & E).
Aneurysmal bone cyst of the mandible. The solid
areas show the features of cemento-ossifying
fibroma and a portion of one of the many cystic
spaces is present at the top of the photomicrograph
(H & E).

117. DIFFERENTIAL DIAGNOSIS
• Conventional ameloblastoma
• CEOT
• Central giant cell granuloma

118. Solitary Bone Cyst

119. Solitary Bone Cyst
• Also called as Hemorrhagic bone cyst, or Traumatic bone cyst.
• Commonly seen in mandible, rare in maxilla.
• Identical to solitary bone cyst of humerus in children and
adolescents.

120. CLINICAL FEATURES
• Age : Young individuals
• Sex : Equal
• Site : Body and symphysis menti of mandible.

121. PATHOGENESIS
• Numerous theories have been proposed.
• First theory – cyst may follow trauma to bone which causes
intra medullary hemorrhage which fails to organize. This clot
subsequently liquefies - CYST.
• Recent theory osteogenic cells fail to differentiate locally and
thus instead of bone, the undifferentiated cells form synovial
tissue.

122. Signs & symptoms
• Asymptomatic.
• Rarely, swelling and pain may be seen.
• Half of all patients give a history of trauma to the area.

123. RADIOLOGICAL FEATURES
• Appears as a lucency with
irregular but well defined
edges and slight cortication.
• On occlusal view the
‘lucency is seen to extend
along cancellous bone.
Radiograph of a solitary bone cyst involving an
extensive area in the right body of the mandible. This
example has a well-defined margin with cortication.
Interradicular scalloping is a prominent feature.

124. HISTOLOGICAL FEATURES
• Lumen not lined by any
epithelium (Pseudo cyst).
• Wall shows loose fibro
vascular connective tissue.
• Hemorrhage and
hemosiderin pigment
usually present.
• Multinucleated giant cells
scattered within the
connective tissue.
• Adjacent bone shows
osteoclastic resorption on
inner surface.
A solitary bone cyst of the jaw. The lining is
composed of loose vascular fibrous tissue with
osteoclastic activity on the surface of the adjacent
bone (H & E).

125. DIAGNOSIS
•
RADIOLOGY
a.
b.
c.
d.
e.
f.
Periapical x-rays
Occlusal view x-rays
Lateral oblique view x-rays
Panoramic x-rays
P.A view x-rays
Sinus view x-rays
•
•
•
•
C.T.SCAN
RADIOPAQUE DYES
ASPIRATION
BIOPSY

126. Various Aspirates
PATHOLOGY
ASPIRATE
Other Findings of Aspirates
Dentigerous Cyst
Clear, pale straw colour
fluid
Cholesterol crystals.
Total protein in excess
4 g / 100ml. Resembles serum
Odontogenic Keratocyst
Dirty, creamy white
viscoid suspension
Para keratinized squames.
Total protein less than
4 g /100ml. Mostly albumin
Periodontal Cyst
Clear, pale yellow straw
colour fluid
Cholesterol crystals.
Total protein 5 — 11g / 100ml
Infected Cyst
Pus, brownish fluid
Polymorphonuclear leukocytes,
,Cholesterol clefts
Mucocele, Ranula
Mucus
-----
Gingival Cysts
Clear fluid
-----

127. Various Aspirates
PATHOLOGY
ASPIRATE
Other Findings of
Aspirates
Solitary Bone Cyst
Serous fluid, blood or
empty cavity
Necrotic blood clot
Stafne’s Bone Cyst
Empty cavity – yield air
---
Dermoid Cyst
Thick sebaceous material
---
Fissural Cyst
Mucoid fluid
----

128. Treatment
• Cysts of the jaws are treated in one of the following four basic
methods:
(1)
(2)
(3)
(4)
Enucleation,
Marsupialization,
A staged combination of the two procedures, and
Enucleation with curettage.

129. Pictorial Conclusion...
129

130. Pictorial Review...
130

131. The biopsy report is as good as the
tissue specimen….
131

133. • References :
1. Cysts of Oral and maxillofacial region, Shear.
2. Contemporary Oral and Maxillofacial
Pathology, Sapp, Eversole, Wysoki.
3. Shafer’s Textbook of Oral Pathology.