Cysts Of The Oral Region - Oral Pathology

CYSTS OF THE
ORAL REGIONS
S A N A R A S H E E D
A K H TA R S A E E D M E D I C A L A N D D E N TA L C O L L E G E

ODONTOGENIC CYSTS
• Cysts derived from Rests of Malassez
i. Periapical Cyst
• Cysts Derived from Reduced Enamel Epithelium
i. Dentigerous Cyst
ii. Eruption Cyst
iii. Paradental Cyst
• Cysts derived from Dental Lamina (Rests of Serres)
i. Odontogenic Keratocyst
ii. Lateral Periodontal Cyst
iii. Gingival Cyst of Adult
iv. Dental Lamina Cyst of Newborn
v. Glandular Odontogenic Cyst

• A cyst is composed of three
basic structures:
• (1) a central cavity (lumen),
• (2) an epithelial lining,
• (3) an outer wall (capsule)
The cystic cavity usually
contains fluid or semisolid material such as
cellular debris, keratin, or mucus.
The epithelial lining differs among cyst types
and may be keratinized or nonkeratinized,
stratified squamous, pseudostratified,
columnar, or cuboidal.
The cyst wall is composed of connective
tissue
containing fibroblasts and blood vessels.
Clinical Importance:
• Destructive.
• They produce significant signs and
symptoms, particularly when they become
large or infected.
True cysts: cysts with an epithelial lining
Pseudocyst: no epithelial lining.

ODONTOGENIC CYSTS
• Odontogenic cysts are derived from three epithelial structures:
• (1) rests of Malassez—remnants of the Hertwig’s epithelial root sheath that persist in
the periodontal ligament after root formation is complete;
• (2) reduced enamel epithelium—residual epithelium that surrounds the crown of the
tooth after enamel formation is complete; and
• (3) remnants of the dental lamina (rests of Serres)—islands and strands of
that originate from the oral epithelium and remain in the tissues after inducing tooth
development.

CYSTS DERIVED FROM RESTS
OF MALASSEZ
• Periapical Cyst
• Other names: Radicular cyst, Apical
periodontal cyst.
• Most common type of odontogenic
cyst.
• Site: root apex of an erupted tooth
with pulp that has been devitalized by
dental caries or trauma

PERIAPICAL CYST PATHOGENESIS
• This cyst arises from the rests of Malassez, which enlarge in response to inflammation
elicited by bacterial infection of the pulp or in direct response to necrotic pulpal tissue.
Because epithelial cells derive their nutrients by diffusion from the adjacent connective
tissues, progressive growth of an epithelial island moves the innermost cells of that island
away from their nutrients.
• Ultimately these innermost cells undergo ischemic liquefactive necrosis, establishing a
central cavity (lumen) surrounded by viable epithelium. At this point an osmotic gradient is
established across the epithelial lining (membrane) separating the connective tissue fluids
from the necrotic contents of the newly formed cyst.
• The net effect of this osmotic gradient is a progressive increase in fluid volume within the
lumen tending to expand the cyst by the internal hydraulic pressure generated.

PERIAPICAL CYST
• CLINICAL FEATURES
• Site: apex of a root adjacent to the pulp canal opening.
• openings of large accessory pulp canals on the lateral aspect of the roots of teeth,
termed lateral periapical (radicular) cysts
• Size: less than 1 cm in diameter.

PERIAPICAL CYST
• RADIOGRAPHIC FEATURES
• Appearance: as a rounded, well-circumscribed, often corticated radiolucency at the
apex of a non-vital tooth.
• Cysts that develop on the lateral aspect of the root appear as semicircular
radiolucencies against the root surface.
• Occasionally a periapical cyst that develops in the anterior maxilla in the apical region
of a lateral incisor tooth will appear as a globulomaxillary radiolucency that may
result in divergence of the roots of the lateral incisor and the adjacent cuspid.

PERIAPICAL CYST
• HISTOPATHOLOGY
• In the cavity lining: cavity lined with a layer of nonkeratinized squamous epithelium of variable
thickness.
• These cysts are typically inflamed, and neutrophils are usually present within the epithelial lining.
• Granulation tissue may be present in some parts of epithelial lining.
• The epithelium and connective tissue may contain laminated crescent-shaped structures termed
hyaline (Rushton) bodies.
• The connective tissue wall (capsule) of the periapical cyst generally exhibits a significant
inflammatory infiltrate consisting of plasma cells, lymphocytes, lipid-laden histiocytes, and
• In the Cyst wall: Multinucleated giant cells associated with crystalline cholesterol deposits and
deposits of hemosiderin are also frequently present in the cyst wall.
• The cystic lumen usually contains proteinaceous fluid and necrotic cellular debris.

• A cyst that remains at the site of a previously extracted tooth is termed a residual cyst

CYSTS DERIVED FROM REDUCED
ENAMEL EPITHELIUM
• Dentigerous Cyst

DENTIGEROUS CYST
• Site: unerupted mandibular or maxillary third molars or maxillary cuspids.
• Regardless of its size, the cyst remains attached to the cervical margin of the affected
tooth. The crown of the tooth is therefore located within the lumen of the cyst and
root remains outside
• asymptomatic but may produce some swelling or pain, particularly if it is large or
inflamed.
• the arch will clinically appear to be missing at least one tooth.

DENTIGEROUS CYST
• RADIOGRAPHIC FEATURES
• A wellcircumscribed radiolucency surrounding the crown of an unerupted tooth
• The interface with the surrounding bone is corticated.
• In the mandible this cyst may displace the associated tooth inferiorly or superiorly
into the ascending ramus.
• In the maxilla it usually displaces the associated tooth superiorly and posteriorly

DENTIGEROUS CYST
• HISTOPATHOLOGY
• Epithelial lining: The cystic cavity of a dentigerous cyst is lined by a relatively uniform
layer of nonkeratinized, stratified, squamous epithelium measuring two to ten cells in
thickness. Inflammation usually alters the epithelial lining. Depending on the type of
inflammation (acute or chronic) and its severity (mild or severe), the epithelial lining
may become hyperplastic, atrophic, or ulcerated. In most cases the inflammation is
usually a mixture of chronic and acute inflammatory cells.
• Some of the incidental microscopic features seen in periapical cysts, including
crystalline cholesterol deposits, hemosiderin deposits, hyaline (Rushton) bodies, and
lipid-laden macrophages are also seen in dentigerous cysts.
• In addition, variable numbers of mucus cells are occasionally seen in the epithelial
lining of this cyst. This finding has been described as either mucus cell metaplasia or
mucus cell prosoplasia.
• Long-standing dentigerous cysts will occasionally exhibit areas of keratinization or
premalignant (dysplastic) changes of their epithelial lining

ERUPTION CYST
• Location: the alveolar soft tissue around the crown of an erupting tooth.
• It is confined to soft tissues so it is a fluctuant swelling of the alveolar ridge rather
an intrabony radiolucency.
• Mastication will occasionally induce hemorrhage in an eruption cyst, giving rise to the
term eruption hematoma.
• Histology same as Dentigerous cyst. Variable numbers of ghosted epithelial cells,
derived from exfoliated lining cells, are often seen within the organizing hemorrhage
that may be present in the lumen of these cysts.

PARADENTAL CYST
• Involved with pericoronitis.
• Also known as, Buccal bifurcation cyst
• Craig cyst
Crown of tooth has cervical enamel
projection as predisposing factor.

PARADENTAL CYST
• PATHOGENESIS
• The reduced enamel epithelium and epithelial rests of Malassez proliferate in
to inflammatory stimuli in the periodontal pocket on the lateral aspect of a vital
• Due to cervical enamel projection
• Due to deep pocket formation
• In partially erupted tooth.

• In young patients may induce Garre’s osteomyelitis – resolves when cyst is removed.

PARADENTAL CYST
• Radiograpic features: a well-circumscribed radiolucency in the periapical or
panoramic radiographs.
• Histopathology:
• Lined by Hyperplastic layer of nonkeratinized squamous epithelium.
• Infiltrated with neutrophils.
• Capsule chronically inflamed.

CYSTS DERIVED FROM DENTAL
L AMINA (RESTS OF SERRES )

WHAT IS DENTAL LAMINA?
Dental lamina is an embryologic strand of epithelium that carries the dental organ to its
destination within the developing fetal jaw.
When functional: dental lamina connects the developing enamel organ to the alveolar
mucosa.
When in post functional period: dental lamina disrupts into small islands and strands of
epithelium termed, rests of dental lamina or Rests of Serres.
Rests of Serres persist in the adulthood and found in the gingival connective tissue and
within underlying alveolar bone.

ODONTOGENIC KERATOCYST
Definition:
A cyst derived from the remnants of dental lamina, with a biologic behavior similar to a
benign neoplasm, with a distinctive lining parakeratinized squamous epithelium of six to
ten cells in thickness, and that exhibits a basal cell layer of palisaded cells (tombstone or
picket fence appearance) and a surface of corrugated parakeratin.

Site:
Any site in the jaw.
2/3rd occur in mandible, primarily in posterior body and the ramus area.
In maxilla: posterior segment or in the cuspid-lateral incisor area.
OKC develops around the crown of an unerupted tooth.
Usually single lesion, but can be multiple cysts.

Has a large growth potential, attains a large size and causes massive bone destruction.
Recurrence rate: 25% to 60% similar to ameloblastoma.
Peripheral OKCs: extraosseuos, occur within gingival soft tissues.

ODONTOGENIC KERATOCYST. REASONS FOR
RECURRENCE?
The first of these is related to their tendency to multiplicity in some patients, including the
occurrence of satellite cysts, which may be retained during an enucleation procedure. If
enucleation procedures are incomplete, some instances of recurrence may be new cysts
arising from retained satellite microcysts or retained mural cell islands.
Second, OKC linings are very thin and fragile, particularly when the cysts are large and are,
therefore, more difficult to enucleate than cysts with thick walls.
Portions of the lining may be left behind and constitute the origin of a recurrence.

OKC: CLINICAL FEATURES
Age: 1st to 8th decades of life, peak during 2nd and 3rd decades.
At least 50% of keratocysts form in the angle of the mandible, extending forwards into
body and upwards into the ramus.
Symptomless until the bone is expanded or they become infected.
Multiple OKCs a feature of Nevoid basal cell carcinoma syndrome (Gorlin Goltz
syndrome)

Difference than other jaw cysts: Why clinical signs fail to appear?
Answer: The main difference is that expansion of the jaw is much less than the
radiographic extent of the cyst. Hence clinical signs often fail to appear until the cyst is
well advanced.

NEVOID BASAL CELL CARCINOMA
SYNDROME

Radiographic features:
Well defined, solitary lesion with smooth or scalloped margins,
Multilocular, polycystic radiolucency exhibiting a thin corticated margin.

OKC HISTOPATHOLOGY
1. Thin uniform lining of parakeratinized squamous epithelium, 6 to 10 cells thick.
2. Pallisaded layer of columnar or cuboidal basal cells.
3. Corrugated luminal surface.
4. Lack of rete pegs.
Adjacent connective tissue is loose and fibrillary and free of inflammation.
Cystic lumen contains desquamated parakeratin.
Occasionally, remnants of dental lamina, microcyst formation, satellite daughter cysts,
epithelial budding from basal cell area seen.

Treatment: surgical enucleation
Surgical resection
Marsupialization before surgical removal

LATERAL PERIODONTAL CYST
Definition:
A slow growing, non expansile developmental odontogenic cyst derived from one or
rests of the dental lamina, exhibiting a lining of one to three cuboidal cells and distinctive
focal thickenings (plaques)

LATERAL PERIODONTAL CYST : CLINICAL
FEATURES
Age: 50 years
Site: premolars
Single or multiple in clusters

LATERAL PERIODONTAL CYST
Radiographic Features:
Small, well defined, delicately corticated, unilocular radiolucency located between the
roots of the vital teeth.
Lesion usually less than 1cm in diameter, found in mandibular premolar region. And in
maxilla, between the cuspid and lateral incisor.
Botryoid variant: polycystic periodontal cyst.

LATERAL PERIODONTAL CYST:
HISTOPATHOLOGY
Thin lining of nonkeratinized squamous or cuboidal epithelium measuring 1 to 3 cells in
thickness.
Variable number of glycogen rich clear cells.
Some cysts have Plaques.
Unicystic or polycystic.

TREATMENT
Surgical enucleation.

GINGIVAL CYST OF THE ADULT
Definition:
A small developmental odontogenic cyst of the gingival soft tissue derived from the rests
of the dental lamina, exhibiting a lining of squamous to cuboidal epithelium with
occasional distinctive focal thickenings similar to those seen in the lateral periodontal

GINGIVAL CYST OF THE ADULT: CLINICAL
FEATURES
Clinical Features:
Firm but compressible fluid filled swelling on the mandibular or maxillary facial gingiva.
Extraosseous
Site: premolar, cuspid and the incisor region.
Age: 40 years and above.

GINGIVAL CYST OF THE ADULT:
RADIOGRAPHIC FEATURES
Not apparent on radiographs.
May cause pressure induced depression (saucerization) in the underlying alveolar bone
that is apparent on radiographic examination.

GINGIVAL CYST OF THE ADULT:
HISTOPATHOLOGY
Lesions are small.
Nonkeratinized epithelum. 2 to 5 cells in thickness, exhibits mural thickenings (plaques)
Clear cells may be present.
Treatment: surgical enucleation.

DENTAL LAMINA CYST OF NEWBORN
• Definition:
• Small, sometimes multiple, raised cystic nodules that occur on the alveolar ridges of
infants;
• they are derived from rests of the dental lamina and consist of a keratin filled cystic

DENTAL LAMINA CYST OF THE NEWBORN
• Cysts are derived from remnants of primary dental lamina that remain in the soft tissues of
the jaws.
• Site : Alveolar ridges of newborn infants
• Appearance: small often multiple swellings

• Histology:
• Superficially located thin walled cystic lesion lined by a
• Thin, stratified squamous epithelium, and containing compacted desquamated keratin.
• Treatment: resolve spontaneously. And require no treatment.

GLANDULAR ODONTOGENIC CYST (SIALO-
ODONTOGENIC CYST)
• Definition:
• A unilocular or multilocular
• Odontogenic cyst derived from the rests of permaent dental lamina and characterized
a
• lining with variable numbers of small intraepithelial glandular structures lined by cuboidal
or columnar cells,
• Often including mucus cells.

ODONTOGENIC CYST)
• Radiographic Features:
• Occurs primarily in the mandible
• Lesions are large
• Appears as well-defined, unilocular, or multilocular radiolucencies.

ODONTOGENIC CYST)
• Histopathology:
• 1. thin squamous epithelial lining that may be relatively uniform in thickness or may
exhibit focal epithelial thickenings (plaques)
• 2. variable numbers of glandular structures or microcysts within the lining epithelium.
• 3. a single layer of columnar or cuboidal cells lining the glandular structures, replacing
surface layer of the stratified squamous epithelium of the cyst lining.
• 4. Glandular spaces contain secretory product.
• 5. Mucus cells resembling goblet cells of the intestinal mucosa and ciliated cells are also
present.

DEVELOPMENTAL
CYSTS OF THE
ORAL REGION
8 / 1 / 2 0 2 0

HOW DO THEY ARISE?
• Cysts are derived from epithelium present during embryonic development.
• Cysts of Vestigial Ducts
• Lymphoepithelial Cysts
• Cysts of Vestigial Tract
• Cysts of Embryonic Skin

CYSTS OF VESTIGIAL DUCTS :
NASOPALATINE DUCT CYST
• Definition:
• An intraosseous developmental cyst
• Of the midline of the anterior palate, near
the incisive foramen
• Derived from the islands of epithelium
remaining after closure of the embryonic
nasopalatine duct.
Also named Incisive canal cyst

• Cysts of the incisive papilla: cysts entirely within soft tissue of the anterior palate

• Radiographic features:
• A well circumscribed oval or heart shaped radiolucency
located in the midline of the anterior maxilla between the
roots of the central incisors.

• In the edentulous maxilla the radiographic diagnosis may not be as obvious as in the
dentate patient.
• Cysts may be asymptomatic or inflamed causing pain, pressure, and swelling.
• Cysts of incisive papilla are in the soft tissue and not evident radiographically.

• Histopathology:
• Lined by layer of pseudostratified ciliated columnar(respiratory), cuboidal, or stratified
squamous epithelium or a mixture of these types.
• If inflammation is present, infiltrate of plasma cells and lymphocytes.
• Cyst capsule: blood vessels and peripheral nerves.
• Small lobules of salivary type mucus glands may be seen in the cyst wall.
• Treatment: surgical enucleation.

NASOLABIAL CYST
• Also known as the nasoalveolar cyst and the Klestadt cyst,
• Location: this rare condition occurs entirely in the soft tissues of the anterior maxillary
vestibule, below the ala of the nose and deep in the nasolabial crease.
• its derivation is from remnants of the inferior and anterior portions of the nasolacrimal
duct.

NASOLABIAL CYST
• This cyst is a unilateral or occasionally bilateral painless soft tissue swelling that results in a
flattening of the nasolabial crease on the skin below the ala of the nose.
• If the upper lip is appropriately retracted, this cyst also can be seen intraorally as a
located at the depth of the maxillary vestibule.
• Age: fourth and fifth decades of life
• Gender: a female predilection of approximately 3 to 1.
• Because this cyst is located entirely within soft tissue, it is not readily apparent
radiographically unless contrast medium is injected into the cystic lumen to facilitate
visualization. Focal pressure-induced bone resorption (saucerization) of the anterior
can be occasionally demonstrated on radiographs and is most readily seen in the
edentulous patient.

NASOLABIAL CYST
• HISTOPATHOLOGY
• The cyst is lined by a layer of pseudostratified columnar epithelium exhibiting variable
numbers of mucus (goblet) cells or by a ductal type of cuboidal epithelium
• A lining of stratified squamous epithelium can be seen in some lesions. Some degree
of folding of the cyst lining and of the associated connective tissue is often seen.
• A narrow zone of dense, homogeneous, fibrous tissue is usually seen adjacent to the
epithelial lining.
• Inflammation is generally absent

ORAL LYMPHOEPITHELIAL CYST
• The oral lymphoepithelial cyst, also termed benign lymphoepithelial cyst, most commonly
develops where extratonsillar lymphoid tissue (oral tonsil) is found.
• The most common sites are the anterior floor of the mouth and the posterior lateral border
of the tongue.
• Pathogenesis: It appears to develop from epithelial invaginations (crypts) that become
detached from the surface mucosa and entrapped within the lymphoid tissue; cyst
formation ensues.
• An alternate theory suggests that the epithelium in these cysts could be derived from minor
salivary ducts that traverse oral lymphoid tissue.

• Location: anterior floor of the mouth and on the posterior lateral borders of the
tongue.
• It can also occur on the ventral surface of the tongue, soft palate, tonsillar pillars, and
oropharynx.
• Appearance and size: It is an asymptomatic, yellowish or tan, superficial submucosal
mass that usually measures less than 1 cm in diameter.

• HISTOPATHOLOGY
• The cyst is lined by a relatively thin layer of parakeratinized squamous epithelium
surrounded by a well-defined mass of normal lymphoid tissue exhibiting variable
numbers of germinal centers.
• The cystic lumen is usually filled with desquamated parakeratin.
• Occasionally, the pore or crypt that communicates between the surface mucosa and
the cystic lumen can be seen microscopically.
• The presence of bacteria within the cystic lumen in some of these cysts is also
that communication with the oral cavity is present.

CERVICAL LYMPHOEPITHELIAL CYST
• The cervical lymphoepithelial cyst, also commonly termed branchial cleft cyst or
benign cystic lymph node.
• Site: occurs on the lateral aspect of the neck, usually anterior to the
sternocleidomastoid muscle.
• Pathogenesis: It is thought to be derived from epithelium entrapped within lymphoid
tissues of the neck during embryologic development of the cervical sinuses or the
second branchial clefts or pouches.
• An alternate theory suggests that the epithelium in this cyst might be derived from
salivary duct epithelium trapped within cervical lymph nodes during embryogenesis

CERVICAL LYMPHOEPITHELIAL CYST
• The cyst becomes apparent in late childhood or early adulthood as a painless swelling on
the lateral aspect of the neck anterior to the sternomastoid muscle.
• A draining fistula that communicates between the cyst and the overlying skin surface
occasionally develops.
• HISTOPATHOLOGY
• The cyst lumen is usually lined by a thin layer of stratified squamous epithelium and
contains desquamated orthokeratin.
• The capsule wall is thickened, consisting of a fibrous connective tissue containing large
numbers of well-formed lymphoid follicles.

THYROGLOSSAL TRACT CYST
• Pathogenesis: derived from embryologic remnants of the thyroglossal tract. This tract
extends from the foramen caecum on the middorsum of the tongue to the thyroid
gland.
• Site: 70% to 80% occur below the hyoid bone.
• This cyst occurs primarily in children and young adults and presents as an
asymptomatic, slowly enlarging, mobile swelling involving the midline of the anterior
neck above the thyroid gland.
• A small percentage of these cysts occur within the tongue, where they can cause
dysphagia.

THYROGLOSSAL TRACT CYST
• HISTOPATHOLOGY
• This cyst is lined by stratified squamous epithelium, ciliated columnar epithelium,
transitional epithelium, or a mixture of epithelial types.
• The cyst capsule can exhibit a number of additional findings including lymphoid
aggregates, thyroid tissue, mucus glands, and sebaceous glands.
• Complications:
• Carcinoma can occasionally develop from the lining of thyroglossal tract cysts and
from remnants of the thyroglossal tract.
• Dysphagia

• The dermoid cyst represents a simple form of cystic teratoma derived from germinal
epithelium entrapped during embryonic development.
• Most of these cysts occur in the head and neck region, primarily in the skin around the
eyes and the anterior upper neck, extending superiorly into the floor of the mouth

• The dermoid cyst is a lesion of young adults (teenagers).
• No gender predilection is seen.
• Cysts of the anterior upper neck or floor of the mouth present as painless swellings
exhibiting a doughy consistency on palpation.
• Cysts that develop above the mylohyoid muscle present as a midline swelling in the
sublingual (floor of the mouth) area. In this location the cyst results in elevation of the
tongue and can interfere with eating and speaking.
• Cysts that develop below the mylohyoid muscle (Figure 2-41, A) appear as a midline
swelling in the submandibular and submental region.
• The size of these cysts is variable, but most are 2 cm or less in diameter.

REFERENCES
• Contemporary Oral and Maxillofacial Pathology - 2nd Edition
• Cawson's Essentials of Oral Pathology and Oral Medicine

Cysts Of The Oral Region - Oral Pathology

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