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Odontogenic Cysts Definition

Cysts lined by odontogenic epithelium


Inflammatory Cysts

Reactive, result or inflammation


Developmental Odontogenic Cysts

Unknown origin, although each type of cyst is thought to
arise from an aberration occurring at some point along the
continuum of normal tooth development


Classes of Inflammatory Cysts

• Periapical (radicular) cyst
• Residual periapical (radicular) cyst
• Buccal bifurcation cyst


Periapical Radicular Cysts basics

Always arises from a tooth with a necrotic pulp
• Often asymptomatic


Periapical cysts radiographic features

• Loss of lamina dura
• Relatively well-circumscribed radiolucency surrounding the apex/root
• May reach a large size


Periapical cysts v granuloma radiographically

radiographically identical


What is the difference
between a cyst and a

The periapical granuloma is an accumulation of chronically inflamed granulation tissue seen at the apex of a nonvital tooth. The radicular cyst is a lesion that develops over a prolonged period of time within an existing periapical granuloma. A cyst, by definition, has an epithelial lining.


Treatment of periapical cysts

endodontic therapy on
the involved tooth, or extraction of the tooth with curettage of
the cystic space. If the lesion does not resolve, seriously
consider biopsy. Don’t keep re-treating the tooth…


Residual Periapical Cyst

Radiographically appears as an
oval or round lucency within the
alveolar ridge at the site of a
previous tooth extraction.
Histology is similar to the
periapical cyst… The clinical
history and radiographic
description that you provide are
necessary to diagnose this


Buccal Bifurcation Cysts

Often develops on the buccal aspect of the
mandibular first permanent molars
• Usually seen in children from 5 to 11 years of age
• Complaints of tenderness, swelling, foul-tasting
• Buccal periodontal pocket may form
• One third of patients have bilateral involvement


Buccal Bifurcation Cyst Radiographical présentation

Radiographs reveal
a well-circumscribed
lucency involving
the bifurcation and


Tx of Buccal Bifurcation Cysts

Treatment consists of enucleation of the cyst
without extraction of the tooth. Complete
healing is usually seen.


Developmental Odontogenic Cysts

• Dentigerous Cyst
• Eruption Cyst
• Odontogenic Keratocyst
• Orthokeratinized Odontogenic Cyst
• Gingival (alveolar) cyst of the newborn
• Gingival Cyst of the Adult
• Lateral Periodontal Cyst
• Calcifying Odontogenic Cyst
• Glandular Odontogenic Cyst


Dentigerous Cysts basics

Defined as a cyst originating
from the separation of the
follicle from around the
crown of an unerupted tooth.
Fluid accumulates between
the reduced enamel
epithelium and the crown.
• Most common developmental
odontogenic cyst, making up
20% of epithelial-lined
gnathic cystic lesions


Clinical presentation of Dentigerous cysts

Most DC’s commonly involve
mandibular third molars,
followed by maxillary canines,
maxillary third molars, and
mandibular second premolars.
• There is a slight male
predilection. The DC is most
often diagnosed between the
ages of 10 and 30.
• They are usually
asymptomatic, and are
discovered incidentally during
radiographic exam.


Dentigerous cysts and bone expansion

Occasionally they may cause painless expansion of the bone upon
reaching a large size.


Dentigerous Cysts communicate with oral cavity

If a DC communicates with the oral cavity (partially erupted tooth
or adjacent periodontal defect), the cyst may become infected, with
subsequent pain and swelling experienced by the patient.


Dentigerous Cyst - Radiographic

• Usually unilocular radiolucency associated with the
crown of an unerupted tooth
• The cyst usually has a well-defined, thin, sclerotic


Radiographic presentation of an infected dentigerous cyst

• An infected cyst may show ill-defined borders
• Large lesions may appear multilocular due to persistence of bony
• Occasional tooth displacement, root resorption


Hyperplastic dental follicle v dentigerous cyst

Some clinicians allow 3-4 mm for a dental follicle. Anything bigger is
often a dentigerous cyst, but COULD also be an odontogenic
keratocyst, ameloblastoma, or another odontogenic entity. Biopsy
and histologic evaluation will provide the final diagnosis.


Dentigerous Cyst – Treatment and

• Removal of the unerupted tooth
• Enucleation of the cyst
• Large cysts may be marsupialized prior to
• Excellent prognosis, low chance of recurrence
• Infrequent bad stuff: ameloblastoma, squamous
cell carcinoma, intraosseous mucoepidermoid


Eruption Cyst

• This is the soft tissue counterpart of the
dentigerous cyst. The associated tooth is only softtissue


Eruption Cyst - Clinical

• This cyst is most often seen in children younger than age 10
• There is a soft, translucent swelling of gingiva located over the
crown of an erupting tooth.
• Blood may be present in the cyst fluid, giving a blue color to the
• Eruption cysts usually involve permanent first molars or maxillary


Erruption cyst radiographically

Radiographically, the erupting tooth
appears normal. The soft tissue is seen
as a slightly radiopaque dome over the
involved tooth


Tx of eruption cysts

These cysts often
spontaneously with
eruption of the tooth
– treatment is usually
not necessary


Odontogenic Keratocyst Basics

OKC’s arise from cell rests of the dental lamina
• It is thought that they do not enlarge by increased osmotic pressure
within the lumen, but from unknown factors inherent in the
epithelium or cyst wall
• Sporadic and syndromic cases are associated with a PTCH tumor
suppressor gene mutation on chromosome 9q22
• 3%-11% of all odontogenic cysts are keratocysts


Odontogenic Keratocyst (OKC/KCOT) -

• 60% diagnosed between age 10
and 40 years
• Slight male predilection
• Mandible, 60%-80% of cases;
propensity for posterior
mandibular body and ascending
• Usually asymptomatic
• May grow large, tend to grow in
an antero-posterior direction
with no bony expansion


Odontogenic Keratocyst (OKC/KCOT) –

• OKC’s display a
lucent area with
smooth, often
• They may


OKC and unerupted teeth

• Associated with an unerupted
tooth in 25% to 40% of cases
• Radiographically similar to
dentigerous cysts when
associated with an unerupted


OKC v dentigerous cyst

• Because they grow in an
anterior-posterior direction,
they have more of a tendency
to expand up the mandibular
ramus than a dentigerous cyst


OKC tx and prognosis

• Because the diagnosis must be made histologically, most
OKC’s are initially treated by enucleation and curettage
• Recurrence rate ~30% (5%-62% according to various
• Adjunctive measures: Peripheral ostectomy, chemical
cauterization with Carnoy’s solution, placement of drains
• The prognosis is good, although some cysts may be more
aggressive, requiring resection. Extension to skull base has
been reported
• Long-term clinical and radiographic follow-up is


OKC and Gorlin syndrome

The presence of multiple odontogenic keratocysts in
the same patient is strongly suggestive of this
aka Nevoid Basal Cell Carcinoma


Nevoid Basal Cell Carcinoma Syndrome

Autosomal dominant inheritance with complete
penetrance and highly variable expressivity
• Mutations in PTCH tumor suppressor gene on
chromosome 9q22.3-q31
• The main characteristics include multiple basal cell
carcinomas of the skin, odontogenic keratocysts,
intracranial calcification, and vertebral and rib
• There are numerous other less common, known
manifestations of NBCCS
• Prevalence is 1 in 60,000


Gorlin and hands and feet

Palmar and plantar pits in 65% of patients


Gorlin and fall cerebra

Over 50% of patients exhibit calcification of the falx


Gorlin Tx and prognosis

Most of the anomalies experienced by patients with NBBCS
are not life-threatening. Treatment occurs as each problem
arises; skin BCC’s are excised, OKC’s are usually curetted.
Basal cell carcinomas of the skin may ultimately cause death
due to invasion of adjacent structures. Patients experience
increased morbidity through the years due to scarring skin


Orthokeratinized Odontogenic Cyst

• An odontogenic cyst with an orthokeratinized epithelial
• Males outnumber females 2:1
• Twice as frequent within the mandible as the maxilla,
most often posterior (both jaws)


OOC radiographic

• Usually unilocular, although they may be multilocular
• 66% present clinically and radiographically similar to
dentigerous cysts; most often associated with the crown of an
unerupted mandibular third molar


OOC Tx and prognosis

• Enucleation and curettage is usually sufficient
• Recurrence rate of 2%, as opposed to
OKC/KCOT with a recurrence rate of over 30%
with curettage


Gingival Cyst of the Newborn

• Superficial, small keratin-filled inclusion cysts on
the alveolar mucosa of infants, 2-3 millimeters in
diameter, usually maxillary
• Related to other inclusion cysts:
– Epstein’s pearls in the midline of the palate
– Bohn’s nodules on the lateral hard and soft palates
• Over half of all newborns are thought to have these


Gingival cysts of newborn tx

• No treatment necessary; spontaneous involution usually occurs by
3 months of age


Lateral Periodontal Cyst

• LPC’s occur along the
lateral tooth root surface,
and they are believed to
arise from the dental
• Usually patients are in
the 5th-7th decades
• 75% to 80% of cases
occur in the mandibular
incisor areas
Well-circumscribed lucency lateral to vital tooth


botryoid odontogenic cyst

Lateral Periodontal Cyst
The lesion may exhibit a polycystic (grapelike) and
multilocular appearance:


Tx of lateral periodontal cyst

Treatment consists of conservative enucleation; low recurrence rate


Gingival Cyst of the Adult

• Considered the soft tissue counterpart to the lateral periodontal cyst
• Arise from rests of the dental lamina (rests of Serres)
• 60% to 75% of cases occur in the mandibular canine and premolar area,
on the facial gingiva or alveolar mucosa; maxillary cysts may also be found
in the incisor region
• Patients are usually in the 5th to 6th decades


Gingival cysts of the adult clinical presentation

Clinically, these cysts present
as painless, dome-like
swellings, sometimes bluishgray
in color.


Gingival cysts of the adult tx

Simple surgical excision, virtually no recurrence


Calcifying Cystic Odontogenic Tumor

• Predominantly intra-osseous; 13% to 30% are peripheral
• Occur in the maxilla and mandible equally, 65% in the
incisor and canine areas
• COC’s may be associated with an odontoma, AOT, or
ameloblastoma in 2% to 14% of cases
• Wide age range, with a mean of 33 years


CCOT radiological findings

• Unilocular, well-defined radiolucency, may be multilocular
• 33% to 50% exhibit irregular calcifications or tooth-like densities
• One third of cases are associated with an unerupted tooth, most
often a canine
• Root resorption and/or divergence is relatively common


What specific histologic finding is associated with CCOT

Ghost Cells


CCOT tx and prognosis

• Good prognosis
• Simple enucleation yields few recurrences


Odontogenic ghost cell carcinoma

– Rare
aggressive variant of COC or odontogenic
ghost cell tumor, characterized by cellular
pleomorphism, mitotic activity, and invasion
of the surrounding tissue. There is a 73% five
year survival for this carcinoma


Glandular Odontogenic Cyst

• Odontogenic origin, also shows glandular or
salivary features (aka sialo-odontogenic cyst)
• Mean age of presentation is 49 years
• 85% of cases are in the mandible
• Predilection for the premolar/incisor region,
and it may cross the mid-line


GOC radiologically

• Radiographically, GOC’s are usually multilocular
with a well-defined margin and a sclerotic rim
• May be aggressive, causing expansion and destruction


GOC tx and prognosis

• Usually treated by enucleation and curettage
• 30% recurrence rate by conservative treatment
• En bloc resection is recommended by some
pathologists and surgeons, due to the potentially
aggressive nature of the GOC
• The GOC is a pitfall for pathologists…
histologically it can look very similar to
mucoepidermoid carcinoma


Odontogenic Carcinoma

• Odontogenic carcinoma may arise from:
• Ameloblastoma or other odontogenic tumor
• De novo (no pre-existing lesion identified)
• Epithelial lining from odontogenic cysts
• 1%-2% of all oral carcinomas reportedly arise from
odontogenic cysts
• The carcinoma usually is squamous cell carcinoma,
although mucoepidermoid carcinoma arising from
mucous cells in dentigerous cysts also has been


Odontogenic carcinoma presentation

• Variable clinical presentation: the carcinoma may
involve pain and swelling, or may be asymptomatic
and discovered incidentally


Developmental Cysts

• Definition
– An epithelial lined cavity that may or may not be filled with
• Cysts often circumferentially increase in size in
response to slowly increasing hydrostatic luminal


Nasopalatine Duct Cyst

• Most common maxillary developmental cyst
• Arises from remnant of the nasopalatine duct
• Radiographic
– Symmetric; oval or heart-shaped radiolucency
between maxillary central incisors
• Teeth are vital
• Treatment
– Curettage



• Arises from entrapped epithelium between
palatal processes
• Some believe this is merely a posteriorlyplaced
nasopalatine duct cyst
• Radiographic
– Symmetric radiolucency, mid-line of hard palate
• Treatment
– Curettage


Globulomaxillary Cyst

• Now considered odontogenic in origin (this cyst does
not exist)
• Radiographic
– Inverted pear-shaped radiolucency between maxillary
canine and lateral incisor, causing divergence of roots


Nasolabial Cyst

• Located entirely in soft tissue (not bone), area
of nasolabial fold
• Typically elevates ala of nose
• Origin from remnants of nasolacrimal duct
• Female predominance (3:1)
• Treatment
– Surgical excision


Developmental Inclusion Cysts of the

• Epstein’s Pearls
– Along median raphe of hard palate
– 75%-80% of all newborns have these
• Bohn’s Nodules
– Along junction of hard/soft palate
• Dental lamina Cyst of the Newborn
– On alveolar ridges
• No treatment necessary, spontaneously resolve


Thyroglossal Duct Cyst

• Origin: Remnants of thyroglossal tract – cyst
may form anywhere between foramen cecum
and thyroid gland
• Firm cystic mass in midline of neck
• May cause dysphagia
• Treatment
– Surgical excision: Sistrunk procedure
• Carcinoma arising in this cyst has been
reported, but rarely


Thyroglossal duct cyst removal

Sistrunk procedure


Branchial Cleft Cyst

• Origin
– Most develop from cystic transformation of salivary gland
epithelium entrapped in cervical lymph nodes
– Some may be fissural in origin
• Cystic mass, lateral neck, near SCM
• Treatment
– Surgical excision
• Carcinoma arising in this cyst is rare; most cases likely
represent metastases to neck lymph nodes from
carcinoma of tonsil or nasopharynx


Epidermoid Cyst/Epidermal Inclusion Cyst

• Ectodermally derived
• May occur anywhere on skin/mucosa
• Mobile nodule with dough-like consistency
• Histology
– Epithelial-lined cyst filled with keratin
• Treatment
– Surgical excision
• Multiple cysts are sometimes associated with
Gardner’s syndrome


Dermoid Cyst

• Location
– Body mid-line: In the head and neck, usually see this in
the floor of the mouth, or neck area if present below the
mylohyoid muscle. Doughy consistency.
• Histology
– Epithelial-lined cyst filled with keratin, containing one or
more skin adnexal structures in cyst wall: sebaceous
glands, hair follicles, sweat glands, smooth muscle
– Two germ cell layers usually (teratoma has 3)
• Treatment
– Surgical excision
• Malignant transformation has been reported, but is


Oral Lymphoepithelial Cyst

• Clinical Features
– White/yellow nodules filled with a creamy/cheesy
keratinous material
– Less than 1cm / firm or soft / Asymptomatic
– Floor of mouth (50%)
– Ventral surface and the posterior lateral tongue
– Palatine tonsil or soft palate
• Treatment
– Surgical excision
– Recurrence rare