FIBRO-OSSEOUS LESIONS OF THE JAWS

INTRODUCTION :

Fibro-osseous lesions are a diverse group of processes that

are characterized by replacement of normal bone by fibrous

tissue containing a newly formed mineralized product. The

designation fibro-osseous lesion is not a specific diagnosis and

describes only a process. Fibro osseous lesions of the jaws

include developmental (hamartomatous) lesions, reactive or

dysplastic processes, and neoplasms.

The pathologic features on a biopsy specimen may be very

similar in lesions of diverse cause, behavior, and prognosis.

Clinical, radiographic, and histopathologic correlation is usually

most beneficial in establishing a specific diagnosis.

WALDRON’S CLASSIFICATION OF FIBRO-OSSEOUS LESIONS

OF THE JAWS

1. Fibrous dysplasia – polyostotic , monostotic

2. Cemento-osseous dysplasia

a.Focal cemento-osseous dysplasia

b.Periapical cemento-osseous dysplasia

c.Florid cemento-osseous dysplasia

3. Ossifying fibroma

1

Although these processes have been grouped under the

encompassing heading of benign fibro-osseous lesions, a more

specific diagnosis often is critical because the treatment of these

pathoses varies from none to surgical recontouring to complete

removal. Although many examples can be diagnosed from the

clinical and radio graphic features, others require knowledge of

the histopathologic, clinical, and radiographic features for an

appropriate diagnosis.

FIBROUS DYSPLASIA

Fibrous dysplasia is a developmental tumor like condition

that is characterized by replacement of normal bone by an

excessive proliferation of cellular fibrous connective tissue

intermixed with irregular bony trabeculae. Although considerable

confusion has existed regarding the nature of fibrous dysplasia,

much has been learned about the genetics of this group of

disorders, and this knowledge makes the wide variety of clinical

patterns more understandable.

Fibrous dysplasia is a sporadic condition that results

from a postzygotic mutation in the GNAS I (guanine-nucleotide-

binding protein (-stimulating.activity polypeptide 1) gene.

Clinically, fibrous dysplasia may manifest as a localized process

involving only one bone, as a condition involving multiple bones,

or as multiple bone lesions in conjunction with cutaneous and

endocrine abnormalities, the clinical severity of the condition

presumably depends on the point in time during fetal or postnatal

life that the mutation of GNAS I occurs.

2

If the mutation occurs in one of the undifferentiated stem

cells during early embryologic life, the osteoblasts, melanocytes,

and endocrine cells that represent the progeny of that mutated

cell all will carry that mutation and express the mutated gene.

The clinical presentation of multiple bone lesions, cutaneous

pigmentation, and endocrine disturbances would result. Skeletal

progenitor cells at later stages of embryonic development are

assumed to migrate and differentiate as part of the process of

normal skeletal formation. If the mutation occurs during this later

period, the progeny of the mutated cell will disperse and

participate in the formation of the skeleton resulting in multiple

bone lesions of fibrous dysplasia. Finally, if the mutation occurs

during postnatal life, the progeny of that mutated cell are

essentially confined to one site, resulting in fibrous dysplasia

affecting a single bone.

Clinical and Radiographic Features

3

Monostotic fibrous dysplasia of the jaw :When the disease is

limited to a single bone, it is termed monostotic fibrous dysplasia.

This type accounts for about 80% to 85% of all cases, with the

jaws being among the most commonly affected sites. Although

the postnatal mutation of GNAS I may occur during infancy,

childhood, or adulthood, most examples of monostotic fibrous

dysplasia are diagnosed during the second decade of life. Males

and females are affected with about equal frequency. A painless

swelling of the affected area is the most common feature. Growth

is gener-ally slow, and the patient or parents are often unable to

recall when the lesion was noted first. Occasionally, however, the

growth may be fairly rapid. The maxilla is involved more often

than the mandible.

Although mandibuar lesions, are truly monostotic, maxillary

lesions often involve adjacent bones (such as the zygoma,

sphenoid, and occiput) and are not strictly monostotic. The

designation of craniofacial fibrous dysplasia is appropriate for

these lesions. Teeth involved in the lesion usually remain firm but

may be displaced by the bony mass.

The chief radiographic feature is a fine "ground-glass"

opacification that results from superimposition of a myriad of

poorly calcified bone trabeculae arranged in a disorganized

pattern. Radiographically, the lesions of fibrous dysplasia are not

well demarcated. The margins blend imperceptibly into the

adjacent normal bone so that the limits of the lesion may be

difficult to define. In the earlier stages, the lesion may be largely

radiolucent or mottled.

4

the lingual and buccal plates but also bulging of the lower

border. Superior displacement of the inferior alveolar canal is not

uncommon. Periapical radiographs of the involved dentition often

demonstrate narrowing of the periodontal ligament space with an

ill defined lamina dura that blends with the abnormal bone

pattern.

When the maxilla is involved, the lesional tissue displaces

the sinus floor superiorly and commonly obliterates the maxillary

sinus. Imaging studies in cases with maxillary involvement may

show increased density of the base of the skull involving the

occiput, sphenoid, roof of the orbit, and frontal bones. This is said

to be the most characteristic radiographic feature of fibrous

dysplasia of the skull.

Polyostotic fibrous dysplasia; Jaffe-Lichtenstein syn-

drome, McCune-Albright syndrome.

5

Involvement of two or more bones is termed polyostotic

fibrous dysplasia, a relatively uncommon condition. The

number of involved bones varies from a few to 75% of the entire

skeleton. When seen with cafe au lait (coffee with milk)

pigmentation, the process is termed Jaffe-Lichtenstcin

syndrome. Polyostotic fibrous dysplasia also may be combined

with cafe au lait pigmentation and multiple endocrinopathies,

such as sexual precocity, pituitary adenoma, or hyperthyroidism.

This pattern is known as the McCune-Albright syndrome.

Although the skull and jaws may be affected with resultant facial

asymmetry, the clinical picture in patients with polyostotic fibrous

dysplasia is usually dominated by symptoms related to the long

bone lesions. Pathologic fracture with resulting pain and deformity

is frequently noted. Leg length discrepancy is very common as a

result of involvement of the upper portion of the femur (hockey

stick deformity).

When present, the cafe au lait pigmentation consists of well-

defined, generally unilateral tan macules on the trunk and thighs.

These pigmented lesions may be con- genital, and pigmented oral

mucosal macules also may be present. The margins of the cafe au

lait spots are typically very irregular, resembling a map of the

coastline of Marine. This is in contrast to the cafe au lait spots are

typically neurofibromatosis, which have smooth borders (like the

coast of California).

6

In McCune-Albright syndrome, sexual precocity is the most

common endocrine manifestation of the syndrome, particularly in

females. Menstrual bleeding may occur during the first few

months of life. Breast development and pubic hair may be

apparent within the first few years of life in affected girls.

Histopathologic Features :

7

The typical microscopic findings of fibrous dysplasia (show

irregularly shaped trabeculae of immature (woven) bone in a

cellular, loosely arranged fibrous stroma. The bone trabeculae are

not connected to each other. They often assume curvilinear shape

& which have been likened to Chinese script writing The bone

trabeculae are considered to arise by metaplasia and are not

surrounded by plump appositional osteoblasts. Fine calcified

spherules may be seen rarely but are never numerous in contrast

to ossifying fibroma and cemento-osseous dysplasia, fibrous

dysplasia typically demonstrates a rather monotonous pattern

throughout the lesion rather than being a haphazard mixture of

woven bone, lamellar bone, and spheroid particle The lesional

bone fuses directly to normal bone at the periphery of the lesion,

so that no capsule or line of demarcation is present though fibrous

dysplasia of the long bones does not undergo maturation, jaw and

skull lesions tend to be more ossified than their counterparts in

the rest of the skeleton this is particularly true in specimens from

older patients. Serial biopsy specimens in some cases have shown

that histopathologically classic fibrous dysplasia of the jaws

undergoes progressive maturation to a lesion consisting of

lamellar bone in a moderately cellular connective tissue stroma.

The bone trabeculae in these mature lesions tend to run parallel

to one another.

Treatment and Prognosis :

8

Clinical management of fibrous dysplasia of the jaws may

present a major problem. Although smaller lesions, particularly in

the mandible, may be surgically resected in their entirety without

too much difficulty, the diffuse nature and large size of many

lesions, particularly those of the maxilla, preclude removal

without extensive surgery. In many cases, the disease tends to

stabilize and essentially stops enlarging when skeletal maturation

is reached. Some lesions, however, continue to grow, although

generally slowly, in adult patients.

Some patients with minimal cosmetic or functional

deformity may not require or desire surgical treatment. Cosmetic

deformity with associated psycho logic problems or functional

deformity may dictate surgical intervention in the younger

patient. Such a procedure usually attempts to remove the entire

lesion entails surgical reduction of the lesion to an acceptable

contour without. The cosmetic result is usually good, but re

growth of the lesion occurs over time.

The prevalence of re growth after surgical reduction is

difficult to determine, but it has been estimated that between

25% and 50% of patients show some regrowth after surgical

shave-down of the lesion. The regrowth is more common in

younger patients, and many surgeons believe that surgical

intervention should be delayed for as long as possible.

9

Malignant change, usually development of an osteosarcoma,

has been rarely associated with fibrous dysplasia. Most examples

have been found in patients who had received radiation therapy

for fibrous dysplasia, but a few examples of spontaneous

sarcomatous changes have been reported. Radiation therapy for

fibrous dysplasia is contraindicated because it carries the risk for

development of post irradiation bone sarcoma.

CEMENTO-OSSEOUS DYSPLASIAS (OSSEOUS DYSPLASIA)

Cemento-osseous dysplasia occurs in the tooth bearing

areas of the jaws and is probably the most common fibro-osseous

lesion encountered in clinical practice. In spite of its frequency,

the associated nomenclature and diagnostic criteria remain an

area of debate.

Because the pathologic features share many similarities with

fibrous dysplasia and ossifying fibroma, correct diagnosis can be

problematic but is critical to appropriate management.

Because cemento-osseous dysplasia arises in close

approximation to the periodontal ligament and exhibits

histopathologic similarities with the structure, some investigators

have suggested these lesions are of perio dontal ligament origin.

Others believe cemento-osseous dysplasia represents a defect in

extra-ligamentary bone remodeling that may be triggered by local

factors and possibly correlated to an underlying hormonal

imbalance.

10

Based on the clinical and radiographic features, it is

convenient to separate cemento-osseous dysplasias into three

groups: (1) focal, (2) periapical, and (3) florid. Although the focal

pattern is somewhat different from the other two forms, it is likely

that these categories may present variants of the same

pathologic process.

Clinical and Radiographic Features

Focal cemento-osseous dysplasia. Focal cemento

osseous dysplasia exhibits single site of involvement. The concept

of focal osseous dysplasia was not clarified until the mid-1990s.

Before that time, most cases were misdiagnosed as a variant of

ossifying fibroma.

An examination of this pattern reveals slightly different

epidemiology from the other two variants. About 90% of cases of

focal cemento-osseous dysplasia occur in females, with an

approximate mean age of 38 and a predilection for the third to

sixth decades. In contrast to the periapical and florid variants, a

higher percentage of cases have been diagnosed in whites.

Focal cemento-osseous dysplasia may occur in any area of

the jaws, but the posterior mandible is the predominant site. The

disease is typically asymptomatic and is detected only on a

radiographic examination. Most lesions are smaller than 1.5 cm in

diameter.

11

Radiographically, the lesion varies from completely

radiolucent to densely radiopaque with a thin peripheral

radiolucent rim. Most commonly, however, there is a mixed

radiolucent and radiopaque pattern. The lesion tends to be well

defined, but the borders are usually slightly irregular. Lesions

occur in dentulous and edentulous areas, with many examples

noted in extraction sites. Occasionally, an apparently focal lesion

may represent an early stage in the transition to multifocal

involvement and, as would be expected, this is seen most

frequently in black females.

Periapical cemento-osseous dysplasia (osseous dysplasia

cemental dysplasia; cementomas). Periapical cemento-

osseous dysplasia predominantly involves the periapical region of

the anterior mandible. Solitary lesions may occur, but multiple

foci are present more frequently. There is a marked predilection

for female patients (ranging from 10:1 to 14:1) and approximately

70% of cases affect blacks. Most patients are diagnosed initially

between the ages of 30 and 50, with the diagnosis almost never

made in individuals under the age of 20 years. Teeth associated

with the lesions are almost invariably vital and seldom have

restorations.

12

Periapical cemento-osseous dysplasia is an asymptomatic

condition that is discovered when radiographs are taken for other

purposes. Early lesions appear as circumscribed areas of

radiolucency involving the apical area of a tooth. At this stage, the

lesion cannot be differentiated radiographically from a periapical

granuloma or periapical cyst. With time, adjacent lesions often

fuse to form a linear pattern of radiolucency that envelopes the

apices of several teeth.

Serial radiographic studies reveal that the lesions tend to

"mature" over time to create a mixed radiolucent and radiopaque

appearance. In the end stage, the lesions show a circumscribed

dense calcification surrounded by a narrow radiolucent rim.

However, the periodontal ligament is intact, and fusion to the

tooth is not seen. Individual lesions seldom exceed 1.0 cm in

diameter.

Each lesion is self-limiting and does not typically expand the

cortex. Progressive growth seldom, if ever, occurs.

Florid cemento-osseous dysplasia. Florid cemento-

osseous dysplasia appears with multifocal involvement not limited

to the anterior mandible. Although many cases demonstrate

multifocal lesions only in the posterior portions of the jaws, many

patients also reveal synchronous involvement of the anterior

mandible. Like the periapical pattern, this form predominantly

involves black women with a marked predilection for middle aged

to the elderly.

13

The lesions show a marked tendency for bilateral and often

quite symmetric involvement, and it is not unusual to encounter

extensive lesions in all four posterior quadrants. The disease may

be completely asymptomatic and, in such cases, is discovered

only when radiographs are taken for some other purpose. In other

instances, the patient may complain of dull pain, and an alveolar

sinus tract may be present, exposing yellowish, avascular bone to

the oral cavity. Although rarely prominent, some degree of

expansion may be noted in one or more of the involved areas.

Radiographically, the lesions typically demonstrate an

identical pattern of maturation noted in the other two forms.

Initially, the lesions are predominantly radio-lucent but with time

become mixed, then predominantly radiopaque with only a thin

peripheral radiolucent rim. On occasion, a lesion can become

almost totally radiopaque and blend with the adjacent normal

appearing bone.

Both dentulous and edentulous areas may be affected, and

involvement appears to be unrelated to the presence or absence

of teeth. More sharply defined radiolucent areas, which on

surgical exploration prove to be simple bone cysts may be

intermixed with the other lesional elements. The cysts may be

single or multiple and, in some cases, represent a sizable portion

of the lesion. It has been suggested that these simple bone cysts

arise from obstruction to drainage of the normal interstitial fluid

by the fibro-osseous proliferation.

Histopathologic Features

14

All three patterns of cemento-osseous dysplasia

demonstrate similar histopathologic features. The tissue consists

of fragments of cellular mesenchymal tissue composed of spindle-

shaped fibroblasts and collagen fibers with numerous small blood

vessels. Free hemorrhage is typically noted interspersed

throughout the lesion.

Within this fibrous connective tissue background is a

mixture of woven bone, lamellar bone, and cementum-like

particles. The proportion of each mineralized material varies from

lesion to lesion and from area to area in individual sites of

involvement. As the lesions mature and become more sclerotic,

the ratio of fibrous connective tissue to mineralized material

decreases. With maturation, the bone trabeculae become thick

curvilinear structures that have been said to resemble the shape

of ginger roots. With progression to the final radiopaque stage,

individual trabeculae fuse and form lobular masses composed of

sheets or fused globules of relatively acellular and disorganized

cementoosseous material.

Diagnosis :

15

In most instances of periapical or florid cemento-osseous

dysplasia, the distinctive clinical and radiographic patterns (i.e., a

black female with multiquadrant involvement or multiple lesions

involving vital lower incisor teeth), allow a strong presumptive

diagnosis without the necessity of biopsy. The features of focal

cemento-osseous dysplasia are less specific and often mandate

surgical investigation. Even upon histopathologic review,

distinguishing focal cemento-osseous dysplasia from ossifying

fibroma often can be difficult. The findings at surgery are very

helpful in discriminating between these two lesions.

Before the final sclerotic stage, cemento-osseous dysplasia

consists of easily fragmented and gritty tissue that can be

curetted easily from the defect but does not separate cleanly from

the adjacent normal bone. In contrast, ossifying fibromas tend to

separate cleanly from the bone and are removed in one or several

large masses.

16

Several histopathologic features also can help to confirm the

impression obtained from the surgical and gross descriptions.

Although cemento-osseous dysplasia and ossifying fibroma

demonstrate a mixture of bone and cementum-like particles, the

trabeculae in ossifying fibroma tend to be more delicate and often

demonstrate osteoblastic rimming. The cementum-like particles in

cemento-osseous dysplasia are irregularly shaped and often

exhibit retraction from the adjacent stroma, whereas those in

ossifying fibroma are more ovoid and often demonstrate brush

borders in intimate association with the adjacent stroma.

Although ossifying fibroma can exhibit hemorrhage along the

margins of the specimen, cemento-osseous dysplasia typically

reveals free hemorrhage throughout the lesion and a sinusoidal

vascularity in close association with the bony trabeculae.

Treatment and Prognosis

The various forms of cemento-osseous dysplasia do not

appear neoplastic; therefore, they generally do not require

removal. However, these lesions can cause significant clinical

problems for some patients. During the predominantly radiolucent

phase, the lesions cause few problems. Once significant sclerosis

is present, the lesions of cemento-osseous dysplasia tend to be

hypovascular and prone to necrosis with minimal provocation. For

the asymptomatic patient, the best management consists of

regular recall examinations with prophylaxis and reinforcement of

good home hygiene care to control periodontal disease and

prevent tooth loss.

17

Because the onset of symptoms is usually associated with

exposure of the sclerotic masses to the oral cavity, biopsy or

elective extraction of teeth should be avoided. In other instances,

symptoms begin after exposure of the sclerotic masses to the oral

cavity as a result of progressive alveolar atrophy under a denture.

Affected patients should be encouraged to retain their teeth to

prevent development of symptoms later.

Management of the symptomatic patient is more difficult. At

this stage, there is an inflammatory component to the disease

and the process is basically a chronic osteomyelitis involving

dysplastic bone and cementum. Antibiotics may be indicated but

often are not effective. Sequestration of the sclerotic cementum-

like masses occurs slowly and is followed by healing.

Saucerization of dead bone may speed healing. Although a single

case of a malignant fibrous histiocytoma arising within a focus of

florid cemento-osseous dysplasia has been reported, such

neoplastic transformation appears unique, and the prognosis for

patients with cemento-osseous dysplasia is good. When simple

bone cysts arise within foci of cemento-osseous dysplasia,

surgical exploration is necessary to establish the diagnosis.

These simple bone cysts often do not heal as rapidly as

those noted in a younger patient who does not have cemento-

osseous dysplasia. In some cases, the cysts persist or enlarge

after surgical intervention; when they fill n, the bone retains an

abnormal radiographic appearance.

To assist healing, the cyst and the surrounding fibro-

osseous proliferation are usually curetted thoroughly.

18

OSSIFYING FIBROMA (CEMENTIFYING FIBROMA; CEMENTO-

OSSIFYING FIBROMA)

Although it can resemble focal cemento-osseous dysplasia

radiographically and, to a lesser extent, histopathologically,

ossifying fibroma is a true neoplasm with a significant growth

potential. Before the refining of the concept of focal cemento-

osseous dysplasia in the mid-1990s, ossifying fibroma was

thought to be a common neoplasm. In reality, true ossifying

fibromas are relatively rare, with many previously reported

examples actually being focal cemento-osseous dysplasia.

The neoplasm is composed of fibrous tissue that contains a

variable mixture of bony trabeculae, cementum like spherules, or

both. Although the lesions do contain a variety of mineralized

structures, most authorities agree the same progenitor cell

produces the different materials. It has been suggested that the

origin of these tumors is odontogenic or from periodontal

ligament, but microscopically identical neoplasms with cementum

like differentiation also have been reported in the orbital, frontal,

ethmoid, sphenoid, and temporal bones, leaving these prior

theories of origin open to question. Today, many authorities prefer

to designate the cementum-like material present in ossifying

fibromas as a variation of bone. The designations ossifying

fibroma, cemento ossifying fibroma, and cementifying fibroma are

all appropriate for this tumor and continue to be used by many.

In spite of this, however, it is agreed that these are the same

lesion and are classified best as osteogenic neoplasms. In this

section, all of these variations will be combined under the term,

ossifying fibroma.

19

Clinical and Radiographic Features

The epidemiology of ossifying fibroma is unclear because

many previous reports confused focal cemento-osseous dysplasia

with true ossifying fibromas. It appears ossifying fibromas occur

over a wide age range with the greatest number of cases

encountered during the third and fourth decades of life. There is a

definite female predilection, with the mandible involved far more

often than the maxilla. The mandibular premolar and molar area

is the most common site.

Small lesions seldom cause any symptoms and are detected

only on radiographic examination. Larger tumors result in a

painless swelling of the involved bone; they may cause obvious

facial asymmetry, which on occasion reaches grotesque size. Pain

and anesthesia are rarely associated with an ossifying fibroma.

Radiographically, the lesion most often is well defined and

unilocular. Some examples show a sclerotic border. Depending on

the amount of calcified material produced in the tumor, it may

appear completely radiolucent, or more often varying degrees of

radiopacity. True ossifying fibromas that become largely

radiopaque with only a thin radiolucent periphery are uncommon:

many reported examples with this radiographic pattern likely

represent end-stage focal cemento-osseous dysplasia. Root

divergence or resorption of roots of teeth associated with the

tumor may be noted. Large ossifying fibromas of the mandible

often demonstrate a characteristic downward bowing of the

inferior cortex of the mandible.

20

Histopathologic Features

At surgical exploration, the lesion is well demarcated from

the surrounding bone, thus permitting relatively easy separation

of the tumor from its bony bed. A few ossifying fibromas will show

grossly and microscopically a fibrous capsule surrounding the

tumor. Most are not encapsulated but are well demarcated

grossly and microscopically from the surrounding bone.

On gross examination, the tumor is usually submitted in one

mass or as a few large pieces. Ossifying fibromas consist of

fibrous tissue that exhibits varying degrees of cellularity and

contains mineralized material. The hard tissue portion may be in

the form of trabeculae of osteoid and bone or basophilic and

poorly cellular spherules that resemble cementum. Admixtures of

the two types are typical. The bony trabeculae vary in size and

frequently demonstrate a mixture of woven and lamellar patterns.

Peripheral osteoid and osteoblastic rimming are usually present.

The spherules of cementum-like material often demonstrate

peripheral brush borders that blend into the adjacent connective

tissue. Significant intralesional hemorrhage is unusual. Variation

in the types of mineralized material produced may be helpful in

distinguishing ossifying fibroma from fibrous dysplasia, which has

a more uniform pattern of osseous differentiation.

Treatment and Prognosis

21

The circumscribed nature of the ossifying fibroma generally

permits enucleation of the tumor with relative ease. Some

examples, however, which have grown large and destroyed

considerable bone, may necessitate surgical resection and bone

grafting. The prognosis, however, is very good, and recurrence

after removal of the tumor is rarely encountered. There is no

evidence that ossifying fibromas ever undergo malignant change.

JUVENILE OSSIFYING FIBROMA (JUVENILE ACTIVE

OSSIFYING FIBROMA; JUVENILE AGGRESSIVE OSSIFYING

FIBROMA)

The juvenile ossifying fibroma is a controversial lesion that

has been distinguished from the larger group of

ossifying fibromas on the basis of the age of the patients, most

common sites of involvement, and clinical behavior. Two different

neoplasms have been reported under the term, and disagreement

exists over the spectrum of what should be accepted as juvenile

ossifying fibromas. Although the two forms demonstrate different

histopathologic and clinical features, several investigators have

chosen to compromise and accept two patterns of juvenile

ossifying fibroma: (1) trabecular and (2) psammomatoid.

Clinical and Radiographic Features

22

No significant sexual predilection is noted in either form. In

most instances, the neoplasms grow slowly, are well

circumscribed, and lack continuity with the adjacent normal bone.

The lesions are circumscribed radiolucencies that in some cases

contain central radiopacities. Those present within a sinus may

appear radio dense and often create a clouding that may be

confused with sinusitis.

The age at diagnosis varies, with reported cases occurring in

patients from less than 6 months to over 70 years of age.

Although both patterns reveal similar radiographic features and

growth patterns, the trabecular form is diagnosed initially in

younger patients. The mean age of trabecular juvenile ossifying

fibromas is approximately 11 years, whereas the age of patients

diagnosed with the psammomatoid variant approaches 22 years.

Both patterns occur in either jaw but reveal a maxillary

predominance. Although many of these tumors are initially

discovered upon routine radiographic examination, cortical

expansion may result in clinically detectable facial enlargement.

The psammomatoid variant frequently appears outside of the

jaws, with over 70% arising in the orbital and frontal bones and

paranasal sinuses.

23

Complications secondary to the neoplasm are typically due

to impingement on neighboring structures. With persistent

growth, lesions arising in the paranasal sinuses penetrate the

orbital, nasal, and cranial cavities. Nasal obstruction,

exophthalmos, or proptosis may be seen. Rarely, temporary or

permanent blindness occurs. Intracranial extension has been

discovered In neoplasms arising adjacent to the cribriform plates.

Because of the circumscribed growth pattern of the tumor, the

frontal lobe is typically elevated without any associated

neurologic signs. Rarely, intracranial extension has resulted in

meningitis, with one report of a maxillary tumor leading to

convulsions and death from pneumococcal meningitis.

Histopathologic Features

Both patterns are typically non encapsulated but well

demarcated from the surrounding bone. The tumor consists of

cellular fibrous connective tissue that exhibits areas that are loose

and other zones that are so cellular that the cytoplasm of

individual cells is hard to discern because of nuclear crowding.

Myxomatous foci are not rare and often are associated with

pseudo cystic degeneration. Mitotic figures can be found but are

not numerous. Areas of hemorrhage and small clusters of

multinucleated giant cells are usually seen.

24

The mineralized component in the two patterns is very

different. The trabecular variant shows irregular strands of highly

cellular osteoid encasing plump and irregular osteocytes. These

strands often are lined by plump osteoblasts and in other areas by

multinucleated osteoclasts. In contrast, the psammomatoid

pattern forms concentric lamellated and spherical ossicles that

vary in shape and typically have basophilic centers with

peripheral eosinophilic osteoid rims. A peripheral brush border

blending into the surrounding stroma is noted in many of the

ossicles. Occasionally, individual ossicles undergo remodeling and

form crescentic shapes.

Treatment and Prognosis :

The clinical management and prognosis of the juvenile

ossifying fibroma are uncertain. Although many tumors

demonstrate slow but progressive growth, some juvenile ossifying

fibromas demonstrate rapid enlargement. The more aggressive

neoplasms tend to arise in infants and young children.

For smaller lesions, complete local excision or thorough

curettage appears adequate. For some rapidly growing lesions,

wider resection may be required.

In contrast to the negligible recurrence rate seen in

the common types of ossifying fibromas, recurrence rates of 30%

to 58% have been reported for juvenile ossifying fibromas.

Malignant transformation has not been documented.

25

REFERENCES:

26

CONTENTS

1) INTRODUCTION

2) WALDRON’S CLASSIFICATION OF FIBRO-OSSEOUS LESIONS

FIBRO-OSSEOUS LESIONS OF THE JAWS

FIBROUS DYSPLASIA

CHERUBISM

CEMENTO-OSSEOUS DYSPLASIA

FOCAL CEMENTO-OSSEOUS DYSPLASIA

PERIAPICAL CEMENTO-OSSEOUS DYSPLASIA

FLORID CEMENTO-OSSEOUS DYSPLASIA

OSSIFYING FIBROMA

JUVENILE AGGRESSIVE OSSIFYING FIBROMA

3) INVESTIGATIONS AND DIAGNOSTIC TOOLS

4) CONCLUSION

5) REFERENCES

* * * * *

DEPARTMENT OF ORAL, MAXILLOFACIAL AND RECONSTRUCTIVE SURGERY

BAPUJI DENTAL COLLEGE & HOSPITAL, DAVANGERE - 577 004.

SEMINAR ON

FIBRO-OSSEOUS LESIONS OF THE JAWS

PRESENTED BYDr. ANNE VIKRAMPost -graduate DEPT. OF O.M.F.R.S.,B.D.C.H.