Chapter 15: Odontogenic cysts and tumors

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Chapter 15 Odontogenic cysts and tumors
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Overview Odontogenic cysts tumors arise from
the odontogenic apparatus. The odontogenic
apparatus consists of Epithelium Remnants of
dental lamina Reduced enamel epithelium
Odontogenic rests Lining of odontogenic cysts
Basal cell layer of oral mucosa Ectomesenchyme
Dental papilla Q What is a cyst? A An
abnormal space within tissue lined by
epithelium. Q Name some cysts that are not
really cysts A Aneurysmal bone cyst, Stafne
bone cyst, Traumatic bone cyst, Simple bone
cyst, Eruption cyst Q Why are they not cysts? A
No epithelial lining!
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The Cysts and Tumors of Chapter 15
Odontogenic cysts Inflammatory Periapical
(radicular) cyst Residual periapical
(radicular) cyst Buccal bifurcation cyst
(usually first molars)
Paradental cysts (partially erupted
third molars Developmental Dentigerous cyst
Odontogenic keratocyst (KOT)
Orthokeratinized odontogenic cyst Gingival
(alveolar) cyst of the newborn Gingival cyst
of the adult Lateral periodontal cyst
Calcifying odontogenic (Gorlin) cyst
Glandular odontogenic cyst Eruption cyst
Odontogenic Tumors Epithelial Tumors
Ameloblastoma Adenomatoid odontogenic
tumor Calcifying epithelial odontogenic
tumor (Pindborg tumor) Squamous odontogenic
tumor Clear cell odontogenic
carcinoma Ectomesenchymal Tumors
Odontogenic myxoma Granular cell
odontogenic tumor Central odontogenic
fibroma Cementoblastoma Mixed Odontogenic
Tumors Odontoma Compound
Complex Ameloblastic fibroma
Ameloblastic fibro-odontoma Ameloblastic
fibrosarcoma Odontoameloblastoma
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Periapical cyst or granuloma (chronic localized
osteitis)
? Impossible to tell radiographically which one
it is only histologically, so you must
include both in your differential diagnosis.
Q Why does a periapical cyst form instead of
just a granuloma? A If by chance there are Rests
of Malassez in the area of inflammation. ? The
rest cells proliferate due to the inflammation
? The ball of cells gets too large, cells in the
center die, center then has a higher protein
concentration, water rushes in to equalize the
osmotic pressure. ? Osmotic pressure can
continue to grow the cyst independent of the
inflammation. Other unilocular radiolucencies
located periapically ? (early) periapical
cemento-osseous dysplasia teeth are vital
? Dentin dysplasia type I teeth are vital,
multiple radiolucencies With a periapical cyst
or granuloma, the tooth is NON-VITAL Take a
vitality test!! ? Tx for a non-vital tooth is
root canal. ? Must biopsy a radiolucent lesion
beneath a vital tooth.
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Dentigerous cyst
? Radiolucency associated with an unerupted
tooth ? encloses the crown of the unerupted
tooth and is attached at the CEJ ? Most common
developmental odontogenic cyst ? Should be the
first differential diagnosis for any radiolucency
associated with an unerupted tooth Others
Odontogenic Keratocyst (KOT), Ameloblastoma
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(Vital teeth)
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Odontogenic Keratocyst(Keratocystic Odontogenic
Tumor)
Can be in the location of ANY other type of
odontogenic cyst or can be isolated in the jaws!
a benign uni-or multicystic, intraosseous
tumor of odontogenic origin lining is
parakeratinized stratified squamous epithelium
potential aggressive, infiltrative behavior
solitary or multiple (multiple usually related to
Gorlin syndrome) Three important things
associated with this diagnosis 1. High
recurrence rate (up to 60) 2. Highly aggressive
(now considered by W.H.O. to be an odontogenic
tumor) 3. Relation to Gorlin syndrome Arises
from the dental lamina or its remnants PTCH
gene is a significant factor in the development
of KOT
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Nevoid Basal CellCarcinoma Syndrome(Gorlin
Syndrome)
Multiple basal cell carcinomas Multiple jaw
cysts (odontogenic keratocysts) Numerous bone
abnormalities including bifid ribs, intracranial
calcification, vertebral anomalies PTCH
gene has been mapped to chromosome 9q22.3 - site
of Gorlin Syndrome Anyone with multiple KOTs
should be tested for Gorlin Syndrome
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Lateral Periodontal Cyst
? The lateral periodontal cyst is generally
quite small and well demarcated. It occurs most
frequently in the mandibular bicuspid area
adjacent to vital teeth. Radiolucencies are
generally small and ovoid ? Derived from
remnants of the dental lamina Tx conservative
enucleation ? Considered to be the intrabony
counterpart to the Adult Gingival Cyst
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Biopsy
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Calcifying Cystic Odontogenic Tumor (Gorlins
cyst)
Uncommon lesion that demonstrates considerable
histopathologic diversity and variable clinical
behavior Can be unilocular or multilocular,
can be associated with an unerupted tooth Tx
simple surgical excision, prognosis is usually
good
Ghost cells calcify
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Biopsy
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Ameloblastoma
Slow growing, non-painful, multilocular,
radiolucent lesion Most common clinically
significant odontogenic tumor Epithelial
origin Average age 33
Tx resection beyond the margins (tumor is to
difficult to remove, and tends to recur)
Peripheral, palisaded cells with nuclei polarized
away from the basement membrane
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Unicystic Ameloblastoma
Account for 10-15 of intraosseous
ameloblastomas Usually occur in younger
patients Because all of the ameloblastoma is
inside the lumen of the cyst, Tx. is removal of
the cyst (not jaw resection) But If
ameloblastoma is in the wall of the cyst,
treatment must be standard for ameloblastoma
resection Can often resemble a dentigerous cyst
around an unerupted 3rd molar
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Biopsy
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Adenomatoid Odontogenic Tumor A.O.T
Young patients Anterior jaws Usually
associated with impacted teeth Easily removed,
therefore small chance of recurrence Tx
curettage
Gland-like structures in a solid tumor of
odontogenic cells
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Biopsy
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Calcifying Epithelial Odontogenic Tumor
(Pindborg Tumor)
Uncommon (less than 200 cases reported to
date) Radiolucent lesion with calcified
radiopacities inside (calcifications are most
often seen in association with an impacted
tooth) Tx local resection
Protein in the amyloid areas is a new,
recently discovered protein
With Congo Red stain the lesion will exhibit
apple-green bifringence when viewed
with polarized light
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Ameloblastic Fibroma
Tumor of both ectodermal and epithelial layers
Younger patients Not generally aggressive,
easily removed if discovered and treated early
If the lesion contains calcifications, then it is
an Ameloblastic Fibro-odontoma
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A.
B.
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Odontoma
Tooth tumor mixed odontogenic tumor A.)
Compound look like little teeth, tooth material
is in correct relation B.) Complex everything
mixed together, no normal relation of tooth
material Tx simple local excision prognosis
is excellent
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Biopsy
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Odontogenic Myxoma
soap bubble appearance aggressive- may
displace or cause resorption of teeth Derived
from odontogenic ectomesenchyme Tx small
lesions can be treated by curattage, but since
the lesion is not encapsulated, the site should
be closely monitored, and large lesions may
require more extensive resection.
Hisologically odontogenic myxomas look just like
dental papilla