unilocular and multilocular radiolucencies

SEMINAR ONUNILOCULAR AND

MULTILOCULAR RADIOLUCENCY

BYDR SOURAV MALHOTRA

IntroductionClassificationAnatomical radiolucencies

Involving mandibleInvolving maxillaInvolving both jaws

Unilocular radiolucenciesMultilocular radiolucencies References

CONTENTS

What is radiolucency ?It express that the region/area/object didn’t absorb the radiation but is transparent/translucent thus more radiation reaches the sensor/film leading to a darker area.

Introduction

What is unilocular radiolucency?From the word uni: means one and lucular means lobes, it means the lesion appears as one mass.

Multilocular radiolucency is produced by multiple

adjacent, frequently coalescing & overlapping

pathologic compartments in bone.

True multilocular lesion contains two or more

pathologic chambers partially separated by septa

of bone.

Soap bubble appearance-

Lesions consists of several circular

compartments that vary in size & usually appear

to overlap

Introduction

Honeycomb-

Lesions whose compartments are small & tend

to be uniform in size

Tennis racket-

Lesions that are composed of angular rather

than rounded compartments that result in

formation of more or less septae. These

compartments tend to be triangular rather,

rectangular or square

UNILOCULAR RADIOLUCENCIES

Singapore Med J 2008; 49(2) : 165

ANAT

OM

ICAL

RADIO

LUCE

NCI

ES

o Structures related to Mandible • Mandibular Foramen • Mandibular Canal• Mental Foramen• Lingual Foramen• Submandibular Fossa• Mental Fossa

o Structures related to Maxilla • Intermaxillary Suture• Incisive Foramen• Nasal Cavity• Nasolacrimal duct/canal• Maxillary sinus

o Structures common to both Jaws• Periodontal ligament space• Marrow Space• Nutrient Canal• Follicular Space

MANDIBULAR FORAMEN

Usually situated just above the mid point in

the medial surface of the ramus & just

posterior to the mid point between the anterior

& posterior borders.

Seen on panographic & lateral oblique films

Outline of foramen varies from triangular to

oval to funnel shaped

Radiographic image is usually upto 1 cm in

diameter

It is associated with relatively radiolucent

mandibular canal that passes from it in an

anteroinferior direction

STRUCTURES RELATED TO MANDIBLE

MANDIBULAR FORAMEN

Lingula may be detected as a triangular radiopacity of

variable density at the foramen’s anterior border

These associated structures, with mandibular canal & lingula,

can be mistaken for pathology

MANDIBULAR CANAL/ INFERIOR DENTAL CANAL:

Largest of the nutrient canals

Seen on panoramic or periapical radiographs of molar region

Appears as relatively radiolucent channel bounded by

definite, thin radiopaque lines (cortical bones) through out its

length

Its course can be followed anteroinferiorly to a point where it

frequently appears to sweep upward to meet the mental

foramen

MENTAL FORAMENAnterior limit of mandibular canal

Mandibular canal send off the

mental canal in the premolar region

This smaller, short canal runs in

superior buccal direction, terminating

with the mental foramen

It is usually located on the

radiograph in the vicinity of premolar

apices.

It may be mistaken for periapical

pathosis when it occurs at the apex of

premolars

LINGUAL FORAMENSeen in relation to lower central

incisors often on periapical views

Located well below the apices of

these teeth in the midline

Seen as radiolucency measuring

usually 1-2mm in diameter

surrounded by prominent

radiopaque ring of cortical bone

Occasionally 2 or more foramina

are seen.

SUBMANDIBULAR GLAND FOSSA

Submandibular fossa is concave area on

the lingual side of the mandible below the

molar area which accommodates the

Submandibular salivary gland

Lies between inferior alveolar canal &

lower cortical margin of mandible

This is seen as relatively radiolucent area

with sparse trabecular pattern which is

sharply limited superiorly by the lower

border of mylohyoid ridge and inferiorly by

lower border of mandible

Shape is round, ovoid or triangular (rarely)

Rarely occurs bilaterally

MENTAL FOSSADepression on the labial

aspect of midline of mandible

just above the mental tubercle

Due to relative thinness of

bone over in this area, it may

be seen as radiolucency over

the incisor roots which may be

mistaken for periapical

pathology

MIDLINE SYMPHYSISSeen on the midline of

the mandible of infants

Seen as radiolucent line

which may be

misinterpreted for fracture

line

Symphysis usually

ossifies by age of 1 year &

then is no longer apparent

MEDIAL SIGMOID DEPRESSION

It is a radiolucency that appears below & just anterior to

greatest depth of sigmoid notch of ramus

Seen on approximately 10% of panoramic radiographs

It is defined by temporal crest & crest of mandibular neck

Its degree of expression is variable depending upon

prominence of these two crests.

SUBLINGUAL GLAND DEPRESSION

First reported by Richard & Ziskind

(1957)

It may develop to accommodate

sublingual salivary gland tissue that lies in

close proximity to the lingual cortex of

mandible in canine region

Most often associated with canines,

followed by incisors & 2nd premolars (rare),

in apical 1/3rd of root

Average size-1.2 cm

Trabeculation may be present within

radiolucency

Have punched out appearance or

corticated margin

STRUCTURES RELATED TO MAXILLA

AIRWAY SHADOWBilateral, relatively radiolucent

Seen on panoramic, lat oblique & cephalomatric radiographs

Results from lack of soft tissue between he posterolateral

surface of tongue & region of soft palate & posterior pharynx

INTERMAXILLARY SUTUREIntermaxillary/ median suture

between right & left maxillary

bones, can be identified as thin

vertical radiolucency in midline

between central incisors

Usually delineated by two thin,

vertical radiopaque lines (cortical

bone).

Generally fuses later in life &

then no longer seen on

radiograph.

INCISIVE FORAMEN, Incisive foramen (anterior palatine

foramen) frequently shows as a

round, oval, diamond shaped or

heart shaped radiolucency that is

well defined on occlusal &

periapical radiographs

The position of foramen on

radiograph ranges from between

the roots of central incisors, close

to alveolar ridge to the level of

apices.

Variability in position of foramen

on radiograph is due to the

angulation of the rays & position of

foramen

SUPERIOR FORAMINA OF INCISIVE CANALS

On radiograph they are seen as

two round or oval radiolucent

areas above the apices of central

incisors in the floor of nasal cavity

near its anterior border & both

sides of nasal septum

In IOPA their image be

superimposed over apices

incisors, which may be

misinterpreted as periapical

pathosis

NASOLACRIMAL DUCT/ CANAL

Nasal & maxillary bones form The nasolacrimal canal

Seen on maxillary occlusal radiograph , projected onto the

posterior hard palate near the 1st or 2nd molar as well defined

radiolucency bilaterally well defined by sharp radiopaque

borders.

On periapical radiographs it may be seen in the region above

the apex of canine, especially if steep angulation is used.

MAXILLARY SINUS

Appear as well defined radiolucency

with thin, sharp radiopaque borders

It shows considerable variation in

size

They enlarge in childhood, achieving

mature size by age of 15 to 18 years

Floors of maxillary sinus & nasal

cavity are seen at approximately same

level at age of puberty in radiograph

In adults sinuses are usually seen to

extend from the distal aspect of canine

to the posterior wall of maxilla above

tuberosity

In older individuals it may extend

farther into the alveolar process &

may extend upto the alveolar ridge

in absence of teeth

STRUCTURES COMMON TO BOTH JAWS

MARROW SPACE

Marrow spaces between trabeculae

of bone appear as radiolucent region

Varies greatly in shape, size &

distribution

Radiographically, in maxilla, they

are generally relatively uniform in

size

In mandible marrow spaces are

smaller & more numerous in the

anterior portion & larger in the

posterior portion

In some persons trabecular

spaces just above & below

the roots of molars are so

large & trabeculae so sparse

that the combined

appearance may resemble &

be misinterpreted as cysts &

other pathosis

These are referred as focal

osteoporotic bone marrow

defects

NUTRIENT CANAL

Appear as ribbonlike

radiolucencies of fairly uniform

width

Carry neurovascular bundles

Seen more often on periapical

mandibular radiographs

Canals become more marked

when teeth are missing

PERICORONAL/ FOLLICULAR SPACE

The crowns of unerupted teeth are

surrounded by dental follicle-

remnant of reduced enamel

epithelium

It is composed of soft myxomatous

to dense collagenous fibrous

connective tissue or cords of

odontogenic epithelium

On radiograph it appears as

homogeneous radiolucent halo

Surrounded by thin outer

radiopaque border representing

compact bone continuous with

lamina dura

Radiolucent halo merges with

periodontal ligament space

Width of halo varies because

of varying thickness of the

follicles & accumulation of fluid

between the capsule of

reduced enamel epithelium &

tooth crown

Normal follicular space – 1.5 to 2 mm

UNILOCULAR RADIOLUCENCIES

PERIAPICAL ABSCESS

The primary abscess develops in a periapical region that

is normal on radiographic examination.

The infection is usually acute and exudative, involving

the periodontal tissues at the apex of the tooth with

necrotic pulp.

The infection and inflammation in the apical area forces

the tooth slightly from its socket, creating an increased

periodontal ligament space around the entire root that is

usually apparent on the radiograph.

The secondary abscess may be of the chronic or the

acute type

Related tooth shows features such as deep restorations,

caries, narrowed pulp chamber, or canals which suggest

that the pulp is non-vital.

The roots of these teeth may show resorption at the

apex.

The tooth is painful on percussion and the patient

complains that it seems ‘high’ to bite on.

Tooth doesnot respond to electric pulp test.

The tooth may demonstrate increased mobility.

In untreated cases the abscess may penetrate the

cortical plate at the thinnest and closest point to the apex

and form a space infection in the adjacent soft tissue.

Periapical radiolucency is a

feature of the secondary abscess.

The radiolucency may vary from

small to quite large to involve much

of the jaw.

The initial periapical lesion may

cause expansion of cortical plate.

In case of acute lesion the

margins of the radiolucency may be

well defined with possibly a

hyperostotic border.

The borders are poorly defined in

case of chronic conditions.

Sometimes the radiolucency is

represented as a blurred area of

somewhat lessened density than

that of surrounding bone.

Radiographic Features

Represents between 69.7% & 94% of all pulpoperiapical

lesions

It is a result of successful attempt by the periapical

tissue to neutralize & confine the irritating toxic products

that are escaping from the root canal

Continual discharge of chronic irritating products from

the canal into the periapical tissue is sufficient to

maintain a low grade inflammation in the tissues which

results in formation of periapical granuloma

PERIAPICAL GRANULOMA

Well circumscribed radiolucency

somewhat rounded & surrounding apex

of tooth

May be surrounded by thin

radiopaque (hyperostoic ) border

Cannot be differentiated from

radicular cyst radiographically alone

Cysts tend to be larger than

granulomas but differentiation on basis

of size is not possible as some cysts are

small & granulomas large

Granulomas are rarely larger than

2.5cm in diameter

Involved tooth is non vital &

asymptomatic


Synonyms-

Periapical cyst

Apical periodontal cyst

Dental cyst

Most common type of cyst in jaw

It results when cell rests of Malassez in the PDL are

stimulated to proliferate & undergo cystic degeneration

by inflammatory products by non vital tooth

Usually asymptomatic unless secondary infection occurs

Incidence is greater in 3rd to 6th decade with slight male

predilection

RADICULAR CYST

Most radicular cysts involve apices of permanent teeth

58% involve lateral incisors

History & clinical features are similar to those of

periapical granuloma

Studies by Lalonde show that such a lesion is more

likely to be a radicular cyst if the periapical radiolucency

tends to be atleast 1.6cm in diameter

An untreated cyst may enlarge slowly & cause

expansion of cortical plates.

In these cases a domelike swelling is seen on the

alveolus over the periapical region of alveolus of involved

tooth

Swelling is initially bony hard on palpation but later it

may demonstrate crackling sound (crepitus) as cortical

plate is thinned

In these cases swelling is rubbery & fluctuant because

of cystic fluid

Radiographic Features LOCATION

Most common site- maxilla (60%)

especially incisors (58%) & canines

In deciduous teeth most commonly

molars are involved

Epicenter is located at the apex of

nonvital tooth

Occasionally it appears on the

mesial or distal surface of root, at

the opening of accessory canal, or

infrequently in a deep periodontal

pocket

PERIPHERY & SHAPE

Usually has well defined cortical border

When cyst becomes secondarily infected due to

inflammatory reaction of surrounding bone, cortex may

be lost or become more sclerotic

Outline is usually curved or circular

EFFECT ON SURROUNDING STRUCTURES

If cyst is large, displacement & resorption of roots of

adjacent teeth may occur

Outer cortical plate of maxilla or mandible my expand in

curved or circular shape

Cyst may displace the inferior alveolar canal in an

inferior direction.

Periapical granuloma & radicular cyst cannot be

distinguished radiographically alone, although

radiolucency with well defined corticated border

more than 2cm diameter, it is more likely to be

cyst.

Differential Diagnosis

Periapical cementoosseous

dysplasia:

Difficult to distinguish

radiographically from

periapical granuloma &

radicular cyst in its early lytic

stage. Tooth is vital in PCOD

Lower teeth especially incisors

more commonly involved

Traumatic bone cyst: Teeth

associated with lesion are vital

Most commonly seen in

mandibular region in molar,

premolar & incisor region

Periapical granuloma does not

have predilection for lower jaw &

more common in anterior region

Lamina dura is intact in traumatic

bone cyst

Dentigerous Cyst

Synonym- Follicular cyst

Most common type of cyst that is formed around

crown of an unerupted tooth

Begins with accumulation of fluid in the layers of

reduced enamel epithelium or between the

epithelium and the crowns of unerupted or

supernumerary tooth

Typically patient has no pain or discomfort

Location

Mandibular 3rd molar or maxillary

canines are most commonly

involved

Epicenter is found just above the

crown of involved tooth

Cyst is attached to the CEJ

Some cyst are eccentric

developing from the lateral

aspect of crown so that they

occupy an area besides the

crown instead of above the

crown


Periphery and Shape

It has well defined cortex

with a curved or circular

outline

Cortex may be missing if

infection is present

Internal Structure

Completely radiolucent

except the crown of

involved tooth

Effects on Surrounding Structure

Displaces tooth involved usually in apical direction

It may also resorb the adjacent teeth

The floor of maxillary antrum may be displaced as the cyst

invaginates the antrum & displace inferior alveolar canal in

inferior direction

It tends to expand outer cortex of involved jaw

Hyperplastic follicle

Size of normal follicular space is 1.5-2mm

If follicular space exceeds 5mm, it is more likely

to be dentigerous cyst.

Tooth displacement & expansion is associated

with dentigerous cyst

DIFFERENTIAL DIAGNOSIS

Odontogenic cyst

Sometimes associated with

unerupted tooth with lesion

present at pericoronal position

Does not cause expansion of

bone

Less likely to resorb teeth

May attach further apically on

root than at CEJ

Ameloblastic fibroma

May be present around

the crown of an unerupted

tooth

Difficult to differentiate

radiographically

Unicystic ameloblastoma

Unilocular ameloblastoma

located around the crown of

an unerupted tooth is difficult

to differentiate

Causes apical displacement of

teeth

Adenomatoid odontogenic

tumour

When completely

radiolucent & associated

with impacted tooth difficult

to differentiate

Attached apical to CEJ

Unicystic Ameloblastoma

Synonyms

Mural Ameloblastoma

Cytogenic Ameloblastoma

Cystic variant of Ameloblastoma

Cystic Ameloblastoma

Intracystic Ameloblastoma

Arises from the wall of cyst

2nd most frequently occurring pathologic pericoronal

radiolucency

Represents approximately 5% of all ameloblastomas

It is associated with following cysts

Dentigerous cysts (85%)

Residual cysts

Radicular cysts

Globulomaxillary cysts

Primordial cysts

Shortly after induction, the tumour begins as mural (within

wall)

When it infiltrates the connective tissue wall of cyst it invades

between the medullary spaces of bone. It than behaves like

conventional ameloblastoma.

Approximately 20% are associated with the crown of

mandibular 3rd molar.

Seen in younger age (average age- 21 years)

Associated with impacted, displaced tooth showing

incomplete root formation

Present as painless swelling

Mandible is more commonly involved

77% were in molar ramus region, 10% in premolar area, 13%

in symphysis

There is pericoronal radiolucency associated with an

unerupted mandibular 3rd molar

Associated teeth is displaced

RADIOGRAPHIC FEATURES

Adjacent erupted 2nd or 3rd molar may show knife edge

pattern of root resorption

Expansion is often present, which tends to be greatest on

buccal aspect

There may be perforation of anterior margins of ramus or at

retromolar pad area

Adenamatoid Odontogenic TumourSYNONYMS

Adenoameloblastoma

Ameloblastic adenomatoid tumour

AOT is uncommon, benign and noninvasive tumour

Makes up approximately 3% of all odontogenic

tumours

CLASSIFICATION

Central

Follicular (73%)

Extrafollicular

Peripheral

Age- 2nd decade

Female predilection (2:1)

Follicular type is associated with unerupted

tooth

Unerupted teeth frequently associated with

tumour in order of frequency are maxillary

canine, lateral incisor & mandibular

premolar

Presents as slow growing painless swelling

Location

75% occurs in maxilla especially in incisor-

canine- premolar region

Has follicular relationship with impacted

tooth but doesnot attach at CEJ, most

often canine is involved or sclerotic border


Periphery

Lesion is well defined with

corticated or sclerotic border

Internal structure

1/3rd of cases show completely

radiolucent lesions

In rest radiopacities are

present within the lesion

Effect on surrounding structures

Causes displacement of teeth

Root resorption rare

May inhibit eruption of tooth

Expansion of jaw may occur

Dentigerous cyst

Associated with impacted teeth but

radiolucent lesion is more apical than CEJ


Odontogenic keratocyst

Difficult to differentiate pericoronal OKC

from AOT radiographically

Synonym

Soft odontoma

Soft Mixed Odontoma

Mixed Odontogenic Tumour

Fibroadmantoblastoma

Granular Cell Ameloblastic Fibroma

Ameloblastic Fibroma

These are benign, true mixed odontogenic

tumours , containing nests & strands of

odontogenic & ameloblastic epithelium in

primitive dental papilla

Calcified odontogenic structures are not

present

Age – below 20 years

Manifests as painless, slow growing

expansion & displacement of involved tooth

May be associated with missing tooth

Location

Mandibular premolar-

molar region most common

site

Tumour may involve ramus

in some cases

Common location is crest

of alveolar process or in

follicular relationship with

an unerupted tooth

It can also arise in an area

where tooth failed to

develop


Periphery

Borders are well defined

& corticated

Internal Structure

More commonly present

as unilocular

radiolucency but may be

multilocular with

indistinct curved septa

Effects on Surrounding Structure

Large lesion can cause expansion of

cortical plates without bone destruction

Associated tooth may fail to erupt or

displaced apically

Hyperplastic Follicle

Dentigerous cyst

Not possible to differentiate either entity

radiographically from ameloblastic fibroma


Multilocular radiolucencies

Ameloblastoma

Cherubism

Odontogenic myxoma

Central hemangioma

Aneurysmal bone cyst

Central giant cell granuloma

Odontogenic keratocyst

Hyperparathyroidism

Ameloblastoma

SYNONYM-

Admantinoma

Adamtoblastoma

Odontomes Embryolastiques

Epithelial Odontomes

It is true neoplasm of odontogenic epithelium, is a

persistent, locally invasive tumour; it has aggressive

but have benign growth characteristics

Represents about 1% of all odontogenic epithelial

tumours & 11% of all odontogenic tumours

Slight male predilection

More common in blacks

Age- 20 to 50 years

Slow growing

Frequently discovered on routine radiographs

Teeth in involved region may be displaced or

become mobile

Location

About 80% develop in

mandibular molar– ramus

region & may extend into the

symphyseal region

In maxilla 3rd molar area is

involved & extends in the

maxillary sinus & nasal floor


Periphery

Well defined &

delineated with a cortical

border

Border is often curved &

in small lesions it may be

indistinguishable from a

cyst

Maxillary lesion are

more ill defined

Internal Structure

Varies from totally

radiolucent to mixed with

bony septae creating internal

compartments

These septae are usually

coarse & curved & originate

from the normal bone that

has been trapped within the

tumour

Internal Structure

Since ameloblastoma

frequently has internal cystic

components, these septae are

often remodeled into curved

shape giving a honeycomb or

soap bubble appearance

Generally loculations are larger

in posterior mandible than in

anterior part

Effects On Surrounding Structures

Causes extensive root resorption

& tooth displacement

Common point of origin is occlusal

to tooth; teeth may be displaced

apically

Occlusal radiograph may show

cyst like expansion & thinning of

adjacent cortical plate, leaving a

thin eggshell of bone

In late stages perforation of bone

into surrounding soft tissues or

anatomic spaces occurs

Unicystic types may cause

extreme expansion of mandibular

ramus

Odontgenic keratocyst

Grows along the bone without

expansion of bone

Differential diagnosis

Giant Cell Granuloma

Occurs anterior to molars

Younger age group

More granular & ill defined

septae

ODONTOGENIC MYXOMA

Both more common in mandible

Ameloblastoma is common in molar- ramus region

Odontogenic myxoma in premolar & molar region & rare in ramus

Straight thin septa seen in odontogenic myxoma whereas curved

coarse in ameloblastoma

Ameloblastoma causes extensive root

resorption

Odontogenic myxoma tends to grow in

length of bone

Ossifying Fibroma

Septae are wide granular & ill defined

SYNONYM

Familial fibrous dysplasia

Cherubism is rare, inherited developmental

abnormality that causes bilateral enlargement of jaws,

giving child a cherubic facial appearance

It is inherited as autosomal dominant trait

It is composed of giant cell like granuloma- like

tissue & does not form bone matrix

Lesion regress with age

Cherubism

Age- 2- 6 years

Presents as painless, firm, bilateral enlargement of

lower face.

Occasionally whole mandible is involved

Maxillary sinus, orbital floor & tuberosity region may

be involved causing stretching of skin of cheeks,

which depresses the lower eyelids, exposing thin line

of sclera (eyes in heaven appearance)

Cherubism

Lesions grow slowly, expanding but not perforating

cortex

Enlargement of submandibular lymph nodes may

occur

By age of 8-9 years of age , growth of pathologic

lesion may stop

At puberty lesion may begin to regress

Usually bony architecture returns to normal by age

of 30 years

Location

Lesion is bilateral

Often both the jaws are affected

When present in only one jaw,

mandible is more commonly

affected

Epicenter is always in posterior

part of jaws, in ramus of mandible,

or tuberosity of maxilla

Lesion grows in anterior direction

In severe cases may extend upto

midline


Periphery

Well defined & in some instances corticated

Internal Structure

Fine granular bony & wispy trabeculae present giving a soap

bubble appearance

Effects On Surrounding Structure

Expansion of maxillary & mandibular cortex occurs

resulting in severe enlargement of jaws

Maxillary lesion enlarges into maxillary sinus

Teeth are displaced in anterior direction as epicenter

is placed in posterior part of jaw

Degree of expansion can be severe resulting in

destruction of tooth buds & incipient follicles

GIANT CELL GRANULOMA

Internal structure has fine,

wispy trabeculae as in

cherubism

Cherubism is bilateral with

epicenter in ramus


MULTIPLE ODONTOGENIC KERATOCYST

Cherubism shows bilateral symmetry with anterior

displacement of teeth & has multilocular appearance


Odontogenic MyxomaSYNONYM

Myxoma

Myxofibroma

Firbomyxoma

Account for 3- 6% of odontogenic tumours

These are benign, intraosseous neoplasm that arises

from odontogenic ectomesenchyme & resemble

mesenchymal portion of dental papilla

Non encapsulated & tend to infiltrate the surrounding

cancellous bone

Age- 10 – 30 years

Slight female predilection

Slow growing painless lesion

If left untreated it grows large & may invade

maxillary sinus

Recurrence rate – 25% (noncapsulated, poorly

defined boundaries, extension of nests or pockets of

myxoid tumour into trabecular spaces)

LOCATION

Most commonly affects mandible (3:1)

Occurs in premolar & molar areas & rarely in ramus

& condylar area

In maxilla, alveolar process in premolar & molar

regions & zygomatic process is involved

PERIPHERY

May be well defined & corticated or poorly defined

(in maxilla)

RADiographic features

INTERNAL SRTUCTURE

It may produce several pattern

Unicystic

Multilocular

Pericoronal

Radiolucent – radiopaque

Residual bone trapped within the bone remodels

into curved or straight, coarse or fine septae giving

multilocular appearance

INTERNAL SRTUCTURE

Characteristically septae

are straight & thin (tennis

racket or step ladder

appearance)

but this pattern is rarely

seen

Majority of septae are

curved & coarse, but finding

one or two of these straight

septa helps in identification

EFFECTS ON

SURROUNDING STUCTURE

Causes displacement &

loosening of teeth but rarely

resorption

Lesion frequently scallops

between the roots of adjacent

structure

Tendency to grow along the

bone without causing much

expansion

AMELOBLATOMA

Both more common in mandible

Ameloblastoma is common in molar-

ramus region

Odontogenic myxoma in premolar &

molar region & rare in ramus

Straight thin septa seen in odontogenic

myxoma whereas curved coarse in

ameloblastoma

Ameloblastoma causes expansion of

bone but odontogenic myxoma grows

along the length of bone

Differential DIAGNOSIS

CENTRAL GIANT CELL

GRANULOMA

Both occur in mandible but CGCG

occurs anterior to 1st molar

septae are ill- defined & wispy &

some are at right angles to the

periphery

CGCG causes expansion of jaws

CENTRAL HEMANGIOMA

Mandible common site but

posterior body , ramus & inferior

alveolar canal is involved

Shows coarse trabecular pattern

OSTEOGENIC SARCOMAS

In odontogenic myxoma a small area of expansion with

straight septae may be projected over an intact bony

cortex & give spiculated appearance resembling

osteogenic sarcoma

But outer cortex is destroyed in odontogenic sarcoma

Hemangioma is a proliferation of blood vessels

Most frequently noticed in skin & subcutaneous

tissues

Central hemangioma is more commonly seen in

vertebrae & skull

Rarely develops in jaws

Lesion may be developmental or traumatic in origin

More prevalent in females (2:1)

Age- 1st decade

Central Hemangioma

Presents as slow, non tender expansion of jaws

It is bony hard in consistency

Pain, if present is probably throbbing type

Some tumours are compressible or pulsate & bruit

may be detected on auscultation

Anesthesia of skin supplied by mental nerve occurs

Bleeding may occur around gingiva around the neck

of teeth

LOCATION

Mandible twice more affected than maxilla

Posterior body & ramus & within the inferior alveolar

canal

Gives a cart wheel apperaence.

Radiographic features

PERIPHERY

Periphery is well defined &

corticated or ill defined

Variation is related to the

amount of residual bone around

the blood vessels

Formation of linear spicules of

bone emanating from the surface

of the bone in sunray- like

appearance can occur when

hemangioma breaks through the

outer cortex & displace the

periosteum

INTERNAL STRUCTURE

Multilocular appearance is due

to entrapment of residual bone

trapped around the blood vessels

Small radiolucent locules may

resemble marrow spaces

surrounded by coarse, dense &

well defined trabeculae

These trabeculae produces

honeycomb pattern composed of

small circular radiolucent spaces

that represent blood vessels

oriented in the same direction of

x- ray beams

Width of inferior alveolar canal, if involved, is increased & shape

becomes serpiginous

Phleboliths are formed when soft tissue is involved

They develop from thrombi that become organized & mineralized

& consists of calcium phosphate & calcium carbonate

EFFECTS ON SURROUNDING STRUCTURES

Roots of teeth are resorbed or displaced

Width of inferior alveolar canal, if involved, is increased & shape changes to

serpiginous path

Mandibular & mental foramen may be enlarged

Involved bone may be enlarged & have coarse internal trabeculae

Developing teeth in contact with hemangioma may be larger & erupt earlier

Aneurysmal Bone Cyst

•Characterized as false cyst as it does not have

epithelial lining

•Age- below 30 years

•Female predilection

•Usually presents as rapid bony swelling

•Pain is occasionally present

•Involved area may be tender on palpation

LOCATION

•Mandible is more commonly involved than maxilla

(3:2) in molar & ramus region

PERIPHERY & SHAPE

•Periphery is usually well defined & shape is circular.


INTERNAL SRTUCURE

•Small initial lesion may show no evidence of an internal

structure

•Often internal structure is multilocular

•Septa is wispy & ill- defined & perpendicular to outer expanded

border


•Causes expansion of outer cortical plates

•Displaces & resorbs teeth

CENTRAL GIANT CELL

GRANULOMA

Both have wispy, ill- defined

trabeculae

Expansion of cortex is more in ABC

than CGCG

ABC is found in molar & ramus area

whereas CGCG in anterior to 1st

molar region


AMELOBLASTOMAABC causes cortical expansion & displaces & resorbs tooth as in ameloblastomaMolar – ramus region common site in bothSeptae are curved, coarse & well defined in ameloblastomaOccurs in older age


CHERUBISMBoth have ill defined, wispy trabeculae & causes expansion of jawsBut cherubism is multifocal & bilateral


Central Giant Cell Granuloma

SYNONYM

Giant cell reparative granuloma

Giant cell lesion, giant cell tumour

Slow growing lesion

Affects mostly adolescents & young adults, usually

below the age of 20 years

Presents as painless swelling

Area is tender on palpation

Overlying mucosa is purple in colour

LOCATION

More common in mandible (2:1)

Epicenter of lesion is usually anterior to 1st molar, although

large lesion can extend posterior to ist molar

Most maxillary lesion arise anterior to canines

Lesions can cross midline

PERIPHERY

Well defined margin in mandible

Lesions in maxilla have ill defined borders


INTERNAL STRUCTURE

Small lesions are completely

radiolucent

Larger lesion show subtle granular

pattern of calcification

Occasionally these calcifications

are organized into ill- defined wispy

septa which are at right angles to the

periphery of the lesion

Sometimes these septa are well

defined & divide the internal aspect

into compartments, creating a

multilocular appearance

EFFECTS ON SURROUNDING

STRUCTURES

Often displace & resorb teeth

Resorption of roots not common

but when it occurs, it may be

profound & irregular in outline

Lamina dura of involved teeth is

absent

Inferior alveolar canal may be

displaced in an inferior direction


Causes expansion of cortical boundaries of jaw

Expansion is uneven or undulating in nature, which

may give appearance of a double boundary when seen

in occlusal radiograph

Outer cortical plate is destroyed in some cases & is

seen more often in maxilla


AMELOBLASTOMA

Occurs posterior mandible

Younger age group

More curved, granular & well

defined septa

CHERUBISM

Internal structure has fine, wispy trabeculae as in

cherubism

Cherubism is bilateral with epicenter in posterior part

of jaw

ODONTOGENIC MYXOMA

Both occur in mandible but CGCG

occurs anterior to 1st molar

septae are sharper & straighter in

OM

CGCG causes expansion of jaws

ABC

Both have wispy, ill- defined trabeculae

Expansion of cortex is more in ABC than CGCG

ABC is found in molar & ramus area whereas CGCG is

anterior to 1st molar region

Odontogenic Keratocyst

*OKC is a noninflammatory odontogenic cyst that

arises from dental lamina

*Accounts for about 1/10th of all cysts in the jaws

*Age- 2nd & 3rd decade

*Male predominance

*Usually asymptomatic

*Pain may occur with secondary infection

*Aspiration may reveal thick, yellow cheesy material

(keratin)

LOCATION

*Site- posterior body of mandible (90% occur posterior

to canine) & ramus (> 50%)

*Epicenter is located superior to inferior alveolar canal


PERIPHERY & SHAPE

*Cortical border is intact unless they have become

secondarily affected

*Has smooth round or oval shape

INTERNAL

STRUCURE

*Most commonly

radiolucent

*In some cases

curved internal septa

may be present,

giving lesion a

multilocular

appearance

EFFECTS ON SURROUNDING

STRUCURES

*Grows along the internal aspect of jaws,

causing minimal expansion

*This occurs throughout the mandible except

for the upper ramus & coronoid process, where

considerable expansion may occur

*Can displace & resorb teeth

*Inferior alveolar canal may be displaced

inferiorly

*In maxilla, it may invaginate & occupy

maxillary antrum

Ameloblastoma

Both have scalloped margins

Ameloblastoma causes

expansion of bone


Odontogenic myxoma

Both shows minimal expansion of

bone

Straight septa present in

odontogenic myxoma

It is endocrine abnormality in which there is an excess of

circulating Parathyroid hormone (PTH)

It causes increase in serum calcium by two processes

An excess of serum PTH increases bone remodeling by

osteoclastic resorption, which mobilizes calcium from

skeleton

PTH also increases renal tubular resorption of calcium &

renal products of active vitamin D metabolite

HYPERPARATHYROIDISM

Types

Primary

Secondary

PRIMARY HYPERPARATHYROIDISM

Occurs due to benign tumour (adenoma) of one of four

parathyroid glands, which produces excess PTH

Diagnosis can be made on basis of hypercalcemia &

elevated serum PTH level

SECONDARY TYPE

Results from compensatory increase in output of PTH in

response to hypocalcemia

Hypocalcemia may be due to

Poor dietary intake

Poor absorption of Vitamin D

Deficient metabolism of Vitamin D in liver or kidney

RADIOGRAPHIC FEATURES OF JAWS

Demineralization & thinning of cortical boundaries often occur in the jaws in

cortical boundaries such as inferior borders, mandibular canal & the cortical

outlines of maxillary sinuses

The densities of the jaws is decreased, resulting in a radiolucent appearance

that contrasts with density of teeth

The teeth stand out in contrast to the

radiolucent jaws

A change in normal trabeculae pattern may

occur, resulting in ground- glass appearance of

numerous small, randomly oriented trabeculae

Brown tumour appear more frequently in

facial bones & jaws, particularly in long

standing cases

Lesions may be multiple within a single bone

Have variably defined margins

May produce cortical expansion

RADIOGRAPHIC FEATURES OF

TEETH & ASSOCIATED

STRUCTURES

Lamina dura is lost (10%) giving

tooth a tapered appearance because

of decreased image contrast

It may occur around one tooth or all

teeth

It may be either partial or complete

REFERENCES Differential diagnosis of Oral & Maxillofacial

lesions- 5th Ed,Wood & Goaz

Oral Radiology -5th Ed White & Pharoah-

Diagnostic Imaging of Jaws- Langland,

Langlais, Nortje

Clinical Outline of Oral Pathology,Eversole

Essentials of Dental Radiology &

radiography,Eric Whaites

Textbook of Oral Pathology- 4th Ed ,Shafer,

Hine, Levy

unilocular and multilocular radiolucencies

Health & Medicine