hyperplasias and benign tumors of the jaws

lecture given 5/21/2026

hyperplasias

torus palatinus, torus mandibularis, hyperostosis, dense bone island

odontogenic tumors

odontogenic epithelial tumors- ameloblastoma, calcifying epithelial odontogenic tumor

mixed odontogenic tumors

odontoma, ameloblastic fibroma, ameloblastic fibro-odontoma, adenomatoid odontogenic tumor

mesenchymal tumors (odontogenic ectomesenchyme)

odontogenic myxoma, benign cementoma

nonodontogenic benign tumors

benign tumors of neural origin- neurilemoma, neuroma, neurofibromatosis

mesodermal tumors

osteoma, gardner’s syndrome, central hemangioma, ossifying fibroma

torus palatinus

palatal torus

bony protuberance at the midline of the palate

located on the hard palate

well defined, convex, or lobulated

homogenously radiopaque

torus mandibularis

mandibular torus

bony protuberance on the lingual aspect of the mandible close to premolar

lingual and bilateral

sharply demarcated

homogenously radiopaque

what is this?

torus palatinus

what is this? besides baby luna

torus mandibularis

hyperostosis

small region of osseous hyperplasia

most commonly on the buccal surface of the maxilla

located on the maxillary alveolar process superimposed on teeth

well or poorly defined

radiopaque and homogenous

dense bone island

aka enostosis, periapical idiopathic osteosclerosis

localized growth of compact bone

located on mandible > maxilla, premolar to molar region

well defined, no capsule

radiopaque

may resorb root- not common but possible

what is this?

hyperostosis

what is this?

dense bone island

general characteristics of benign tumors

abnormal new growth of cells

non-malignant/non-cancerous tumor

localized, and does not spread to other parts of the body

if left untreated, some can grow large and lead to serious disease because of their size

can impinge upon and damage adjacent structures

what radiograph techniques are ideal for examining benign tumors?

intra orals, occlusal, panoramic radiographs

additional imaging CBCT, CT, MRI

what are the radiographic features of benign tumors?

odontogenic lesions- alveolar process, above IAN

vascular & neural lesion- within IAN

cartilaginous tumors- mandibular condyle

smooth, well defined, corticated

internal structure is radiolucent or radiopaque, or mixed, curved septa

can cause displacement of adjacent structures

ameloblastoma

true neoplasm of the odontogenic epithelium

divided into multicystic, unicystic (mural), and desmoplpastic types

men>women, age 20-50, slow growing, symptoms occur early on, increasing facial asymmetry

what are the radiographic features of ameloblastoma?

most often in molar ramus region, may extend into symphyseal area, in maxilla is 3rd molar area

well defined, curved, in the maxilla the periphery may be ill defined

internal structure is radiolucent and septated

can cause root resoprtion, expansile in mesio-distal and bucco-lingual direction, tooth displacement, thinning of the cortical plates, on CT the cortical plates may show perforation, displacement of IAN inferiorly

what are the differential diagnoses for ameloblastoma?

OKC, odontogenic myxoma, dentigerous cyst

what is this?

ameloblastoma

what is this?

ameloblastoma with luna

what is this?

ameloblastoma

what is this?

ameloblastoma

what is this?

ameloblastoma, but on CBCT

what is this?

luna inside an ameloblastoma

what is this?

ameloblastoma

calcifying epithelial odontogenic tumor (CEOT)

aka pindborg tumor

rare, located within bone, produce mineralized substance

men>women, age 8-92, expansile lesion

what are the radiographic features of CEOT?

mandible:maxilla 2:1, premolar to molar region, 52% with uninterrupted tooth

well defined cyst like cortex or irregular and ill defined

uni or multilocular, scattered radiopaque foci close to crown

can cause displacement of teeth or prevent eruption, expansile

what are differential diagnoses for CEOT?

adenomatoid odontogenic tumor, ameloblastic fibro-odontoma, dentigerous cyst

what is this?

an important image of a CEOT

what is this?

CEOT

what is this?

CEOT

odontoma

aka compound odontoma, complex odontoma, odontogenic hamartoma

radiographically and histologically characterized by production of mature enamel, dentin, cementum, and pulp

compound or complex

interfere with eruption

compound odontoma

multiple, well defined teeth

found mostly in anterior maxilla with crown of unerupted teeth

complex odontoma

nondescript mass of dental tissue

found mostly in mandible, 1st and 2nd molars

what are the radiographic features of odontomas?

well defined, smooth or irregular, corticated border wtih a radiolucent area adjacent

radiopaque, differ based on type

can cause impaction, malpositioning, distema, or malformation

what are differential diagnoses of complex odontomas?

periapical cemental dysplasia

what is this?

complex odontoma

what is this?

odontoma

what is this?

compound odontoma

what is this?

compound odontoma

what is this?

compound odontoma

ameloblastic fibroma

aka fibroadamantoblastoma, granular cell ameloblastic fibroma, mixed odontogenic tumor

mixed odontogenic tumor characterized by neoplastic proliferation of the epithelium

age 5-20, missing tooth, painless slow growing

*age is the key

what are the radiographic features of ameloblastic fibroma?

mandible, premolar to molar region, follicular relationship with unerupted tooth

well defined and corticated with cystic manner

unilocular and in rare cases multilocular

in large lesions can expand the cortical plates, prevent the eruption and displace the tooth in apical direction

what are differential diagnoses for ameloblastic fibromas?

dentigerous cyst, hyperplastic follicle, ameloblastoma

what is this?

ameloblastic fibroma

ameloblastic fibro-odontoma

ameloblastic fibroma with enamel and dentin within the lesion

age 5-20, missing tooth

what are the radiographic features of ameloblastic fibro-odontomas?

posterior aspect of the mandible, epicenter is occlusal to the developing tooth

well defined and corticated

mixed lesion, radiolucent with radiopacities, impacted tooth

what are the differential diagnoses for ameloblastic fibro-odontomas?

ameloblastic fibroma, odontoma

what is this?

ameloblastic fibro-odontomas

what is this?

ameloblastic fibro-odontoma

what is this?

ameloblastic fibro-odontoma

adenomatoid odontogenic tumor

adenoameloblastoma and ameloblastic adenomatoid tumor

noaggressive tumors of odontogenic epithelium

age 5-50, 70% at 2nd decade, female > males 2:1, slow growing, painless, associated with missing teeth

what are the radiographic features of adenomatoid odontogenic tumors?

~75% in maxilla, incisor, canine, premolar region

well defined, corticated, or sclerotic border

mixed appearance, calcification seen with well/ill defined borders

can displace teeth, root resportion is rare, may inhibit too eruption

what are differential diagnoses for adenomatoid odontogenic tumors?

OKC, dentigerous cysts

what is this?

adenomatoid odontogenic tumor

what is this?

adenomatoid odontogenic tumor

odontogenic myxoma

aka myxoma, myxofibroma, fibromyxoma

not encapsulated and intend to infiltrate the surrounding cancellous bone

slow growing, high recurrance rate

what are the radiographic features of odontogenic myxoma?

mandible:maxilla 3:1, premolar to molar region, rarely in ramus and condyle, maxilla: alveolar process at premolar to molar and zygomatic process

mmost often poorly defined margin

multilocular/unilocular, straight septa

can displace and loosen teeth, expansile

additional imaging with CT, particularly MRI

what are the differential diagnoses for odontogenic myxoma?

ameloblastoma, CGCG, central hemangioma

what is this?

odontogenic myxoma

what is this?

odontogenic myxoma

what is this?

odontogenic myxoma

benign cementoblastoma

aka cementoblastoma and true cementoma

slow growing, bulbous growth at the apex of the tooth root

males > females, age 12-65, tooth is vital and painful

what are the radiographic features of benign cementoblastoma?

mandible 78%, premolar and 1st molar ~90%

well defined radiopacity with corticated border

radiopaque internal structure

can cause external root resorption, expansion with intact cortical plates

what are differential diagnoses for benign cementoblastoma?

periapical cemental dysplasia, hypercementosis, periapical sclerosing osteitis

what is this?

benign cementoblastoma

what is this?

benign cementoblastoma

neurilemmoma

aka schwannoma

arising from schwann cell, no potential for malignancy

slow growing, swelling, paresthesia

what are the radiographic features of neurilemmoma?

mandible:maxilla 10:1, expanded IAC

margins are well defined, corticated, fusiform

internal structure is uniformly radiolucent, may have scalloping outline

can cause enlargement of the foramen, may cause root resorption

what are the differential diagnoses of neurilemmoma?

vascular lesions such as hemangioma or AV fistula

what is this?

neurilemmoma

what is this?

neurilemmoma

neuroma

aka amputation neuroma and traumatic neuroma

NOT a neoplasm, over-growth of severed nerve

slow growing reactive hyperplasia, that become larger >1cm, pain

what are the radiographic features of neuroma?

mental foramen > anterior maxilla > posterior mandible

well defined, corticated, varies in shape

internal structure is radiolucent

may cause some expansion of IAC

what are the differential diagnoses of neuroma?

NOT possible to differentiate this lesion from other neural lesions

what is this?

neuroma

*neurofibromatosis

aka von recklinghausen disease

syndrome with cafe au lait spots on the skin, multiple peripheral nerve tumors and other dysplastic abnormalities

most common genetic diseases, 2 major classifications NF-1 (generalized) and NF-2 (central)

*what are the radiographic features of neurofibromatosis?

alteration to the shape of the mandible

enlargement of the coronoid notch

an obtuse angle between body and ramus

deformity of condylar head

lengthening of condylar neck

lateral bowing and thinning of ramus

enlarged IAC, mental, and mandibular foramen

erosive changes to outer cortex

interference with normal eruption

what is this?

neurofibromatosis

what is this, and what are the pink line demonstrating?

neurofibromatosis

obtuse angle of mandible and enlargement of the coronoid notch

osteoma

may arise from cartilage or embryonic periostium

asymmetry caused by the swelling and painless

cortical type in men, cancellous type in women

what are the radiographic features of osteoma?

mandible > maxilla, lingual side of the ramus of the mandible or inferior mandibular border apical to molars, condyle and coronoid process, paranasal sinus

well defined

interal structure is uniformly radiopaque

can cause displacement of adjacent structures

what are the differential diagnoses for osteoma of head of condyle and coronoid process?

osteochondroma, osteophytes or condylar hyperplasia

osteochrondroma

what is this?

osteoma

what is this?

osteoma

gardner’s syndrome

aka familial multiple polyposis

syndrome, hereditary, multiple osteomas, dense bone islands, epidermoid cysts, subcutaneous desmoid tumors and mutliple polyps of small and large intestine

what are the radiographic features of gardner’s syndrome?

multiple dense bone islands

osteomas most commonly seen in frontal, mandible, maxilla, and sphenoid bones

more than 5 dense bone islands you should consider a syndrome

multiple unerupted teeth permanent and supernumerary

what is this?

gardner’s syndrome

what is this?

gardner’s syndrome

central hemangioma

proliferation of blood vessels creating a mass, resembling a neoplasm, central type is intraosseous

females > males, slow growing, non tender, expansile, bruit detected on auscultation

what are radiographic features of central hemangioma?

mandible > maxilla 2:1, posterior body and ramus within IAC

may be well defined/ill defined, linear spicules of bone emanating with periostium displaced

internal has mixed appearance, coarse internal trabeculae

can resorb or displace teeth, enlargement of IAC and mental foramen, premature eruption

further imaging with MRI, CT with contrast, conventional angiography

what are differential diagnoses of central hemangioma?

myxoma, osteogenic sarcoma

what is this?

central hemangioma

what is this?

central hemangioma

what is this?

central hemangioma

ossifying fibroma

aka cemento-ossifying fibroma, cementifying fibroma, juvenile aggressive ossifying fibroma

indolent to aggressive behavior, usually in young adults, females > males

what are radiographic features of ossifying fibroma?

mandible, premolar to molar area

well defined

internal structure is mixed, radiolucent, or radiopaque

can cause displacement of adjacent structures, root resorption

what are the differential diangoses for ossifying fibroma?

fibrous dysplasia, POD