Cysts of Oral Cavity

• 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).
DEFINITION OF CYST
2

• 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
TYPES OF CYSTS
3

Cyst has following parts:
• WALL (made of
connective tissue)
• EPITHELIAL LINING
• LUMEN OF CYST
4
PARTS OF A CYST

• TWO STAGES
1. Cyst initiation
2. Cyst enlargement or
expansion
6
PATHOGENESIS
a. Initiation
b. Formation
c. Enlargement

• 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.
CYST INITIATION
7

THEORY
Harris (1974) Postulated the theories
1) Mural growth
a) Peripheral cell division
b) Accumulated contents
2) Hydrostatic
a) Secretion
b) Transuduation & exudation
c) Dialysis
CYST
ENLARGEMENT
8

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.
Mechanism regarding
enlargement
9

FACTORS
1. Secretions:
Mucus secreting cyst – Lining secretes mucus – accumulation of mucus – increase in volume
2. Transudation & exudation: Inflammatory cyst or Presence of infection.
a. Inflammatory cells release cofactors
b. Lymphocytes release lymphokine
c. Osteoclast activating factor (OAF) &
d. Monocytes release interleukin- I
3. Increased osmolarity:
a. Raises internal hydrostatic pressure.
b. Attracts fluid into the cavity.
c. Retention of fluid within the cavity
Increase in the
volume
10

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
Frequency of Epithelial Cysts of Jaws
11

• 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 and the tooth
crown.
13

• 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
CLINICAL
FEATURES
14

• 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.
Signs & symptoms
15

• 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.
RADIOLOGICAL FEATURES
16

• Internally, a dentigerous cyst is completely radiolucent except
for the crown of the involved tooth.
• A dentigerous cyst may displace and resorb adjacent teeth.
• Dentigerous cyst can displace the associated tooth in an
apical direction, away from the cyst’s epicentre.
17

A central type of dentigerous cyst. Note resorption of
the root of the first mandibular molar
Radiographic features
19

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
20

CT scan of a maxillary dentigerous cyst extending
to, and impinging on, the floor of the nose.
21

DIFFERENTIAL DIAGNOSIS
22
1. Odontogenic keratocyst
2. Ameloblastoic fibroma
3. Unicystic amaeloblastoma
4. Adenomatoid odontogenic tumor

COMPLICATIONS
23
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.

• 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 growt h mechanism and biologic behavior from
themore common dentigerous cyst and radicular cyst.
• Odontogenic kerato cysts. and their growth may be related to unknown facto
rs inherent in the epit helium itself or enzym atic activity in the fibrous wall.
25

• AGE : It occur over a wide age range and cases have been
recorded as early as the first decade and as late as
the ninth.
• In most series there has been a pronounced peak
frequency in the second and third decades.
• GENDER : more frequently in males than in females.
• SITE : The mandible is involved far more frequently than
the maxilla
• 50% cases occur in angle region and extend to
ascending ramus and forwards to body of
mandible.
CLINICAL FEATURES
26

Relative distribution of
odontogenic keratocysts in the jaws.
siTE diSTRIbuTION
27

• 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.
CLINICAL FEATURES
28

• 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
29

• 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
RADIOGRAPHIC FEATURES
30

• OKSs have a well defined and corticted periphery, which can
be smooth but its border may scallop a thick bone cortex.
• It grow through the bone without significant bone
expansion, tunnelling type of growth pattern may be seen.
• OKCs occasionally displace teeth and resorb roots, but to a
lesser degree than dentigerous cyst.
31

Radiograph of a small odontogenic keratocyst.
32

Radiograph of an odontogenic keratocyst with scalloped
margins.
33

Radiograph of a multilocular odontogenic keratocyst.
34

Radiograph of an odontogenic keratocyst that has
enveloped an unerupted tooth to produce a
‘dentigerous’ appearance.
35

36
• 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.

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.
37

• 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.
39
Eruption cysts involving the maxillary permanent
incisors.

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

CLINICAL FEATURES
41
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

Radiological features
42
• 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.

CALCIFYING
ODONTOGENIC CYST
43

• Also called as Odontogenic ghost cell cyst or Gorlin
cyst.
• It Has many features of odontogenic tumor, therefore
it is 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).
44

• Age : Wide range, peak in 2nd decade.
• Gender : Equally in both gender
• Site : Anterior segment of both jaws
Clinical FeAtures
45

• 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.
46

• 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
Classification of the odontogenic ghost cell lesions
47

• 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.
Signs & symptoms
48

• 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
49
RADIOLOGICAL
FEATURES
Radiograph of a calcifying odontogenic cyst of
the maxilla. There is a well-demarcated margin
and calcifications suggestive of tooth material.

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.
50

• Based on radiographic appearance, following lesions
must be included in the provisional diagnosis –
• Ameloblastoma
• CEOT
• AOT
• Ameloblastic fibro odontoma
51

Nasopalatine Duct
(Incisive Canal) Cyst
52

• 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.
53

• Age : 4th, 5th & 6th decades.
• Sex : More in females
• Frequency: Commonest non odontogenic
developmental cyst
CLINICAL FEATURES
54

• 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.
PATHOGENESIS
55

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.

• 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.
58

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.
59

Shows a large round radiolucency. The roots of the
maxillary incisor teeth are displaced laterally.
60

• Radicular cyst, if it is associated with a
pulpally involved tooth.
• Large incisive canal.
DIFFERENTIAL
DIAGNOSIS
61

• 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.
NASOLABIAL CYST
63

• Age : Peak incidence in 4th & 5th decades.
• Sex : More in females.
• Frequency: Rare in occurrence.
Clinical features
64

• 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.
65
Signs &
symptoms
Nasolabial cyst producing a swelling of the right
upper lip, forming a bulge in the labial sulcus.

• 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.
PATHOGENESIS
66

• 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.
67
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.

• 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.
69

1. PHASE OF INITIATION:
• Accepted generally that rests of Malassez included within a
developing periapical granuloma proliferates to form the lining of
radicular cyst.
• How these cells are stimulated is not clear.
• Some product of non vital pulp can be responsible which
simultaneously evokes an inflammatory response in CT.
• Immune factors also held responsible as plenty of plasma cells are
seen in a periapical granuloma.
PATHOGENESIS
70

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.
PATHOGENESIS
71

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.
PATHOGENESIS
72

• Age : peak in 3rd, 4th and 5th decades.
• Sex : Slightly more in males.
• Site : Maxillary anterior region.
• Frequency: Commonest cystic lesion of jaws.
CLINICAL
FEATURES
73

• 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.
Signs & Symptoms
74

• 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.
75
Radiograph of a radicular cyst. The lesion is a well
defined radiolucency associated with the apex of a non-
vital root filled tooth.

• 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”.
77

• 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.
78

• 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
79

80
Radiograph of an aneurysmal bone cyst involving the angle and
ascending ramus of the mandible. There is a ballooning expansion
of the cortex.

• Conventional ameloblastoma
• CEOT
• Central giant cell granuloma
81

REASONS
• Cysts tend to increase in size.
• Cysts tend to get infected.
• Cysts weaken the jaw. ( pathological fracture)
• Some cysts undergo changes. Eg: Ameloblastoma,
Mucoepidermoid carcinoma ( histological study to be
done)
• Cysts prevent eruption of teeth. (dentigerous cyst)
• Involvement of neighboring structures.( maxillary
sinus, nose, adjacent tooth)
Principles of
Treatment
83

1. To remove the lining totally or to remove a part of lining to
enable the body to rearrange the position of abnormal tissue
so that it is eliminated from within the jaws.
2. To preserve important adjacent structures such as nerves and
healthy tissues.
3. To achieve rapid healing of the operation site.
4. To restore the part to a near normal form and to restore
normal function.
Aims
of
Treatment
84

1. Marsupialization (Partch 1 Operation) (Cystotomy)
• Combined Decompression & enucleation
• Marupialization through nose or antrum
2) Enucleation (Partch 2 Operation) (Cystectomy))
• a) Enucleation & packing
• b) Enucleation & primary closure
• c) Enucleation & primary closure with
reconstruction / bone grafting
85

• RADIOLOGY
a. Periapical x-rays
b. Occlusal view x-rays
c. Lateral oblique view x-rays
d. Panoramic x-rays
e. P.A view x-rays
f. Sinus view x-rays
• C.T.SCAN
• RADIOPAQUE DYES
• ASPIRATION
• BIOPSY
DIAGNOSIS
86

87
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 -----

Various Aspirates
88
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 ----

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