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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
Radiographic Features
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
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
Radiographic Features
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
RADIOGRAPHIC FEATURES
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
DIFFERENTIAL DIAGNOSIS
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
RADIOGRAPHIC FEATURES
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
DIFFERENTIAL DIAGNOSIS
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
RADIOGRAPHIC FEATURES
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
RADIOGRAPHIC FEATURES
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
DIFFERENTIAL DIAGNOSIS
MULTIPLE ODONTOGENIC KERATOCYST
Cherubism shows bilateral symmetry with anterior
displacement of teeth & has multilocular appearance
DIFFERENTIAL DIAGNOSIS
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.
Radiographic features
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
EFFECTS ON SURROUNDING STRUCTURES
•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
DIFFERENTIAL DIAGNOSIS
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
DIFFERENTIAL DIAGNOSIS
CHERUBISMBoth have ill defined, wispy trabeculae & causes expansion of jawsBut cherubism is multifocal & bilateral
DIFFERENTIAL DIAGNOSIS
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
Radiographic features
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
EFFECTS ON SURROUNDING STRUCTURES
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
Differential diagnosis
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
RADIOGRAPHIC FEATURES
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
Differential diagnosis
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