2. Benign Tumors of the Jaws

slide 1-6

how do benign tumors effect surrounding structures: cortical bone?

• expansion

• thinning

• erosion (in case of aggressive benign lesions)

how do benign tumors effect surrounding structures: maxillary sinus?

displacement

what surrounding structures can be affected by benign tumors?

• manidbular canal (displaced)

• maxillary sinus (displaced)

• cortical bone (expansion, thinning, erosion)

• teeth (displaced)

Displacement mandibular canal (No neuro-sensory deficits)

how do benign tumors effect surrounding structures: teeth?

• Displacement of teeth

• May prevent eruption of teeth

• Root Resorption → “chopped-off” horizontally

how do benign tumors effect surrounding structures: mandibular canal?

displacement (no neuro-sensory deficits)

slide 11

• Ameloblastoma

• Adenomatoid odontogenic tumor

• Calcifying epithelial odontogenic tumor

• Squamous odontogenic tumor

• Clear cell odontogenic carcinoma

What type of tumors?

epithelial tumors

• Odontogenic myxoma

• Cementoblastoma

• Odontogenic fibroma

• Granular cell odontogenic tumor

What type of tumors?

Ectomesenchymal Tumors

• Odontoma

• Ameloblastic fibroma

• Ameloblastic fibro-odontoma

• Odontoameloblastoma

• Ameloblastic fibrosarcoma

What type of tumors?

Mixed tumors

what is a slow-growing, locally-invasive, benign tumor and is the second most common odontogenic tumor?

Ameloblastoma

what are the 3 patterns of ameloblastomas?

• 75-86% (Conventional) ameloblastoma

• 13-21% Unicystic ameloblastoma

• 1-4% Peripheral ameloblastoma

what is the average age of Ameloblastoma patients?

35 years

is there a gender predilection with Ameloblastoma?

no

Ameloblastomas occur >80% in the maxilla/mandible (which one?)

mandible (usually molar region)

how do Ameloblastomas present symptomatically?

• Often asymptomatic

• Usually presents as painless swelling

• Rare pain or paresthesia

Ameloblastomas

how do ameloblastomas radiographically present?

• well circumscribed, corticated

• radiolucent

• unilocular/multilocular (coarse/curved septae)

• expansile

• Tooth displacement/root resorption

ameloblastomas

• well circumscribed, corticated

• radiolucent

• unilocular/multilocular (coarse/curved septae)

• expansile

ameloblastoma

• Pericoronal/mural; impacted tooth

• Displacement of #32

• Osseous expansion

• Thinning of cortices

• Displacement of inferior alveolar nerve canal

ameloblastoma

• Multilocular

• Root resorption

• Thinning of inferior mandibular border

ameloblastoma

• Multilocular

• Septae appear coarse

• Thinning of inferior mandibular border

• Displacement of teeth

• Displacement of inferior alveolar nerve canal

ameloblastomas may arise in the wall of a ____

cyst (mural ameloblastoma)

what are histopathologic patterns of ameloblastomas?

• Follicular

• Plexiform

• Acanthomatous

• Granular cell

• Basal cell

• Desmoplastic

what are the key microscopic histopathologic appearance of ameloblastomas?

Follicular pattern

• Nests of epithelium

• Island centers resembling stellate reticulum

• Peripheral columnar cells with nuclei polarized opposite basement membrane (sub-nuclear vacuolization)

• Mature fibrous background

Desmoplastic pattern

• Compressed islands and cords of odontogenic epithelium in densely collagenized stroma

ameloblastoma (Island centers resembling stellate reticulum)

what treatment is indicated for ameloblastomas?

controversial

• simple enucleation

• curettage

• marginal resection

• long-term follow up required

what is the recurrence rate after curettage of ameloblastomas?

50-90%

what is the recurrence rate after marginal resection of ameloblastomas?

15%

ameloblastoma

% of Unicystic Ameloblastomas are diagnosed between ages 10-20

50%

Unicystic Ameloblastomas have a predilection for what location?

posterior mandible

radiographically, Unicystic Ameloblastomas often mimic what?

dentigerous cysts

Unicystic Ameloblastomas

expansion/thinng ext. oblique ridge

what are 3 types of Unicystic Ameloblastomas?

1. luminal type → tumor confined to luminal surface

2. intraluminal type → tumor nodules project from lining into lumen

3. mural type → tumor islands in wall of cyst

slide 44

what treatment is indicated for Unicystic and peripheral Ameloblastoma?

• Luminal and intra-luminal types treated with enucleation and follow-up

• Mural type treatment debatable

what is the recurrence rate for Unicystic Ameloblastoma?

10-20%

• Painless, non-ulcerated gingival nodule

• Resembles pyogenic granuloma or fibroma

• Usually < 1.5cm

• Superficial alveolar bone may be eroded

What benign tumor?

Peripheral Ameloblastoma

what is the average age of Peripheral Ameloblastoma?

52

which jaw do Peripheral Ameloblastoma have a predilection for?

manible

slide 49-54

what demographics are affected by Adenomatoid Odontogenic Tumor? and what location is there a predilection for?

Age: 70% 10-20 years

Location: 70% maxilla, 90% anterior

Sex: female>male

what are the radiographic findings of Adenomatoid Odontogenic Tumor?

• Well circumscribed, corticated

• Unilocular or multilocular

• Associated with unerupted tooth

• Mixed radiodensity

• Displacement of adjacent teeth

Adenomatoid Odontogenic Tumor

• Well defined, corticated

• Mixed density (predominantly radiolucent with some radiopacity within)

• Associated with impacted maxillary lateral incisor

• Displacement of adjacent teeth

what are histopathologic features of Adenomatoid Odontogenic Tumor?

• Well-defined lesion usually surrounded by thick fibrous capsule

• Spindle-shaped epithelial cells in sheets, strands, or whorled masses of cells in scant fibrous stroma

• Tubular or duct-like structures

• Scattered calcifications represent abortive enamel formation, dentinoid, or cementum

what treatment is inidicated for Adenomatoid Odontogenic Tumor? how common are recurrences?

• Completely benign

• Enucleates easily from bone

• Very rare recurrences

Calcifying Epithelial Odontogenic Tumor is also known as…?

Pindborg tumor

Calcifying Epithelial Odontogenic Tumor makes up % of odontogenic tumors

<1%

what demographics are affected by Calcifying Epithelial Odontogenic Tumor? predilection for which jaw?

• age range: 8-92 (mean age = 36)

• mandible

• rare peripheral tumor

slide 66-69

what are radiographic findings of Calcifying Epithelial Odontogenic Tumor (Pindborg tumor)?

• Well circumscribed, corticated

• Mixed density- central radiolucency with radiopaque foci

• Maybe associated with unerupted tooth

• Expansile- expands cortex

• Root resorption possible

Calcifying Epithelial Odontogenic Tumor (Pindborg tumor)

what are histopathologic features of Calcifying Epithelial Odontogenic Tumor (Pindborg tumor)?

• Islands, strands, or sheets of epithelial cells in fibrous stroma

• Calcifications form concentric Liesegang rings

what treatment is indicated for Calcifying Epithelial Odontogenic Tumor (Pindborg tumor)?

• Less aggressive than ameloblastoma

• Conservative resection recommended

• Good prognosis

what is the recurrence rate of Calcifying Epithelial Odontogenic Tumor (Pindborg tumor)?

15%

what demographics are affected by Odontogenic Myxoma? predilection for which jaw?

• Average age 25-30

• No significant gender predilection

• Posterior mandible most commonly affected

how do Odontogenic Myxoma present symptomatically?

• Small lesions asymptomatic

• Larger lesions associated with painless swelling

what are radiographic findings of Odontogenic Myxoma?

• Variable margins

  • Well defined or poorly defined

• Radiolucent

• Multilocular

  • Few straight septae

  • Curved septae seen as well

• Expansile- expands cortical margins

• Tooth displacement

Odontogenic Myxoma

• well-defined

• multiple septum (thin, straight)

• displacement of 29 root

• expansion of inferior border of mandible

• radiolucent

Odontogenic Myxoma

• well defined corticated

• displacement of 30, 29

• external root resorption of 30

• displacement of IAN canal

• erosion of inferior border of mandible

what are histopathologic features of Odontogenic Myxoma?

• Loose stroma with collagen fibrils

• Haphazardly arranged stellate, spindle-shaped, and round cells

• Inactive rests of odontogenic epithelium may be present

• May be misdiagnosed as hyperplastic dental follicle

what treatment is indicated for Odontogenic Myxoma?

• Small lesions treated with curettage and 5 yr follow-up

• Larger lesions resected

what is the recurrence rate of Odontogenic Myxoma?

25% (Egg-white consistency makes complete removal difficult)

what demographics are affected by Cementoblastoma?

• Equal gender incidence

• Most patients less than age 20

• 75% occur before age 3

how do cementoblastomas present symptomatically?

67% of patients report pain and swelling

cementoblastoma

how do cementoblastomas present radiographically?

• Multiple punctate radiopacities within a welldefined radiolucency

• Homogeneous radiopaque mass

  • Mass attached to 1st mandibular molar roots

  • Obscured root outline, resorption

  • Radiolucent halo - continuity with PDL

  • Sclerotic border

cementoblastomas are in continuity with …?

root of a tooth (this feature differentiates it from osteoblastomas)

slide 92

cementoblastomas

• external root resorption 30

• displacement of IAN canal inferiorly

• thinning/expansion of inferior border of mandible

slide 92

cementoblastoma

slide 94-98

what treatment is indicated for cementoblastomas?

• Extraction of tooth with calcified mass

• Alternative therapy involves excision of mass, involved root amputation, and endodontic therapy

what is the recurrence rate of cementoblastomas?

tumor does not recur + excellent prognosis

what is the #1 most common odontogenic tumor/hamartoma?

odontoma

• 74% of odontogenic tumors in USA

• More common than all other odontogenic tumors combined

what are odontomas composed of?

enamel, detin, pulp, and/or cementum

what are 2 types of odontomas?

compound and complex

what are radiographic findings of odotomas?

• Well defined, corticated

• Radiolucent band/soft tissue capsule inside the cortical border

• Internal content is largely radiopaque

• Maybe associated with unerupted tooth

COMPOUND odontomas

• Well defined, corticated

• Radiolucent band/soft tissue capsule inside the cortical border

• Internal content is largely radiopaque- made of multiple tooth like structures called denticles

• Maybe be associated with unerupted tootH

COMPLEX odontomas

• Well defined, corticated

• Radiolucent band/soft tissue capsule inside the cortical border

• Internal content is largely radiopaque- made of irregular mass of calcified tissue

• Maybe be associated with unerupted tooth

• Possible displacement of teeth (30, 29)

Compound –Complex Odontoma

• Well defined

• Mixed density, corticated

• Combination of amorphous radiopaque mass and tooth like structures

• Osseous expansion

• Thinning of cortices

• Displacement of teeth, unerupted tooth

what are histopathologic features of compound odontomas?

multiple structures resemble small teeth in loose fibrous matrix

what are histopathologic features of complex odontomas?

• mature tubular dentin with structures that contained enamel before decalcification

• 20% show ghost cells

• thin layer of cementum around mass

slide 107-110

what treatment is indicated for odontomas?

• Conservative enucleation

• Prognosis is excellent

what are radiographic findings of osteomas?

• Well defined radiopaque mass

• Internal structure- uniformly radiopaque or internal trabecular structure

• Maybe be exophytic, extending into adjacent soft tissue

osteomas

• bone and teeth are very radiopaque

what are histopahtologic features of osteomas?

• Compact lamellar bone with fibrofatty marrow

• Identical to tori and exostoses

what condition?

• Multiple osteomas, multiple dense bone islands

• multiple unerupted supernumerary and permanent teeth

• epidermoid cysts, subcutaneous dermoid tumors,

• multiple polyps of small and large intestines. The polyps have a strong predilection for malignant transformation

Gardner’s Syndrome

slide 118-119

what are histopathologic features of Central Vascular Malformation?

Proliferation of capillaries and endothelial cells containing abundant blood

what are surface bony growths/bone hyperplasias called?

Exostosis/Torus

what are internal counterpart of exostoses called?

enostosis (dense bone island)

how do torus palatinus present radiographically?

• Dense radiopaque shadow attached to the hard palate

• Well defined periphery, may have convex or lobulated outline

• Maybe superimposed over roots of teeth

what is a hyperostosis that protrudes from lingual aspect of mandibular alveolar process?

Torus mandibularis

what area are Torus mandibularis located?

premolar area, bilaterally

how do Torus mandibularis appear radiographically?

Radiopaque shadow with defined borders superimposed over roots of teeth

how do enostosis appear radiographically?

• Well defined periphery but may blend with trabeculae of surrounding bone

• No effect on teeth but rarely associated with root resorption