Imaging in dental neoplasms by Dr. Bom BC

1. IMAGING IN DENTAL NEOPLASMS
DR BOM B. C.
MD RADIODIAGNOSIS RESIDENT
NAMS, BIR HOSPITAL

2. INTRODUCTION
 Pathologic conditions affecting the jaw are common
yet not frequently imaged or encountered by
radiologists.
 So it is important for radiologists to recognize
pathologic changes in the jaw to ensure appropriate,
timely patient care.
 In cases of infection, the diagnosis typically is known
on the basis of the clinical findings.
 Imaging studies may be needed to assess the extent of
disease and to aid in treatment planning.

3.  Imaging findings may not lead to a specific diagnosis,
but they should narrow the differential diagnosis and
guide further workup.
 Often, jaw abnormalities present in a nonspecific
manner, making imaging of utmost importance in
elucidating the cause of the symptoms.
 The common jaw tumors and tumorlike lesions are
ameloblastoma, osteochondroma, giant cell tumor,
multiple myeloma, osseous metastatic disease,
follicular, apical & primordial cyst, periapical
cementoma, fibrous dysplasia, necrotizing fasciitis,
and osteomyelitis.

4. Embyology
 Each tooth develops from ectodermal cells that
develop into ameloblasts and other outer tooth
regions and ectomesenchymal cells that form the
odontoblasts and dental papillae.
 This process begins at the crown of the tooth and
continues toward the root.
 Four stages of odontogenesis have been described,
including the bud, cap, bell, and crown (apposition)
stages.

5.  During the sixth week of embryonic development,
mesenchymal cells thicken and form the primary
dental lamina.
 These cells begin to invaginate to form a tooth bud
with an overlying cap.
 By the 20th week, the tooth bud appears bell shaped
with active ameloblastic and odontoblastic cells.
 Ameloblastic cells produce tooth enamel whereas
odontoblastic cells form the dentin.

6.  The production of enamel requires the complete
formation of the underlying dentin.
 Both of these processes are completed during the
crown stage, as the tooth enters the final stage of
development.
 Prior to completion of odontogenesis, both the
primary and secondary dental laminae disappear. So,
any remnants of these embryonic cells may give rise
to both benign and malignant lesions later in life.

7.  The remaining ectomesenchymal cells surrounding a
tooth create the dental sac, which contains the
periodontal ligament and cementum.
 The periodontal ligament is a thin fibrous ligament that
attaches the cementum of each tooth to the surrounding
alveolar bone (lamina dura).
 This highly vascularized connective tissue allows limited
motion of each tooth during mastication and also serves to
provide sensation.
 Secured to respective mandible and maxilla by these
components the teeth migrate into the oral cavity and the
developmental process is complete

8. Odontogenesis and tooth anatomy. (a) Drawings illustrate the major stages of tooth
development: the bud stage, cap stage, bell stage, and crown stage. Pink oral epithelium,
brown dental mesenchyme, dark blue ameloblasts, light blue odontoblasts, yellow dentin,
white enamel, red pulp. Although mandibular lesions may originate from cells of early tooth
development, they often do not manifest until later in life.
(b) Radiograph demonstrates the anatomy of a mature tooth. Lesions of the mandible
typically arise from characteristic locations within and surrounding a tooth.

9. Anatomy
 The bulk of a tooth is formed of dentine, which is sensitive
to temperature change and other stimuli.
 In the centre of the tooth crown and down the root to the
tooth apex, is a hollow space occupied by the pulp, which is
soft tissue containing nerves and vessels.
 The crown projects from the gingiva and is protected by a
layer of enamel in the form of a thimble or cap which is
insensitive and hard, like ivory (= elephant enamel) but is
susceptible to caries.
 Beyond the crown there is a thin layer of cementum
covering the dentine of the root and this layer forms the
anchorage for the periodontal membrane or ligament
which slings the tooth in its bony socket.

10.  The bony anchorage for the fibres of the periodontal
membrane is a thin layer of compact bone lining the socket
called the lamina dura beyond which is the cancellous
bone of the alveolar process (the tooth-supporting bone) of
the jaw and this is covered with a thin layer of compact
bone beneath the gingiva.
 Enamel is denser to X-rays than dentine which is
comparable in density to compact bone while the pulp
space is more lucent than dentine.
 The thin layer of cementum covering the root beneath the
gingiva is radiographically indistinguishable from dentine.
 The cancellous bone forming the alveolar process surrounds
the sockets on at least three sides.

11. Normal tooth anatomy. (a) Drawing shows normal tooth anatomy. Enamel (E)
covers the crown, and a thin layer of cementum (arrowhead) covers the roots.
Dentin (D), a calcified matrix, lies between the enamel or cementum and the
pulp chamber (P) or root canal. Cementum and dentin cannot be distinguished
at imaging because they have similar mineralization. The pulp chamber and
root canal contain neurovascular elements. Gingiva (G) covers the maxillary
and mandibular alveolar processes (B). In teeth with multiple roots, the space
between the roots is called the furcation (F). Lamina dura (curved arrow), a
thin layer of dense bone, lines the socket. The periodontal ligament (straight
arrow) lies between the lamina dura and cementum. * = cementoenamel
junction, dashed line = dentinoenamel junction. (b) Digital periapical
radiograph of maxillary molars shows enamel (E), dentin (D), pulp chamber
(P), alveolar process (B), lamina dura (curved arrow), and periodontal ligament
space (straight arrow). Amalgam (black *) and composite fillings (white *) are
also seen. Arrowheads = superimposed maxillary sinus wall. (c) Magnified
sagittal oblique CT image of a mandibular molar shows the enamel (white
arrow), dentin (black *), pulp chamber (white *), pulp or root canal (!), and
periodontal ligament space (black arrow), which is radiolucent.

12. Tooth numbering nomenclature for primary and permanent teeth. (a) Illustration shows the
universal numbering system (ADA), which uses letters A–T, and the FDI numbering system,
which uses numbers 51–55, 61–65, 71–75, and 81–85, for primary teeth. Blue = molars, red =
incisors, yellow = canines. (b) Illustration shows the universal numbering system (ADA), which
uses numbers 1–32, and the FDI numbering system, which uses numbers 11–18, 21–28, 31–38,
and 41–48, for permanent teeth. Blue = molars, green = premolars, red = incisors, yellow =
canines.

13. WHO Classification Scheme for
Odontogenic Tumors (1992)
A. Neoplasms and other tumors related to the odontogenic apparatus
Benign
 Odontogenic epithelium without odontogenic ectomesenchyme
Ameloblastoma, squamous odontogenic tumor, calcifying epithelial
odontogenic tumor (Pindborg tumor),
clear cell odontogenic tumor
 Odontogenic epithelium with odontogenic ectomesenchyme, with or without
dental hard-tissue formation
Ameloblastic fibroma, ameloblastic fibrodentinoma (dentinoma) and
ameloblastic fibro-odontoma, odontoameloblastoma, adenomatoid
odontogenic tumor, calcifying odontogenic cyst, complex odontoma,compound
odontoma
 Odontogenic ectomesenchyme with or without included odontogenic
epithelium
Odontogenic fibroma, myxoma (odontogenic myxoma, myxofibroma), benign
cementoblastoma (cementoblastoma,true cementoma)

14. Malignant
 Odontogenic carcinoma
Malignant ameloblastoma, primary intraosseous
carcinoma, malignant variants of other odontogenic
epithelial tumors, malignant changes in odontogenic
cysts
 Odontogenic sarcomas
Ameloblastic fibrosarcoma (ameloblastic sarcoma),
ameloblastic fibrodentinosarcoma and ameloblastic
fibro-odontosarcoma
 Odontogenic carcinosarcoma

15. B.Neoplasms and other lesions related to bone
 Osteogenic neoplasms
• Cemento-ossifying fibroma (cementifying fibroma, ossifying fibroma)
 Nonneoplastic bone lesions
• Fibrous dysplasia of the jaws
• Cemento-osseous dysplasia
Periapical cemental dysplasia (periapical fibrous dysplasia), florid
cemento-osseous dysplasia (gigantiform cementoma, familial
multiple cementomas), other cemento-osseous dysplasia
• Cherubism (familial multilocular cystic disease of the jaws)
• Central giant cell granuloma
• Aneurysmal bone cyst
• Solitary bone cyst (traumatic, simple, hemorrhagic bone cyst)
 Other tumors
• Melanotic neuroectodermal tumor of infancy (melanotic progonoma)

16. Cystic Lesions
 A true cyst forms when developmental or
inflammatory factors stimulate proliferation of
epithelial cells surrounding a tooth.
 As these cells grow, the central cells become removed
from their nutrient supplied by adjacent vascular
connective tissue and become necrotic.
 Subsequently, an epithelium-lined cavity or sac is
formed.

17.  Cysts appear radiologically as well defined lucent areas
within the bone.
 Although most cysts have a sclerotic rim, severe
underlying inflammation may result in a decreased
degree of sclerosis.
 Cysts are classified according to the cell of origin, with
the majority of cysts in the jaw arising from
odontogenic sources.

18. The three common types of dental cyst.
(A) Radicular cyst. The tooth is carious, the cyst sits at the apex of the bone and
absorbs the local lamina dura.
(B) Dentigerous cyst. The cyst is related to the crown of an unerupted tooth.
(C) A large cyst which is not related to a dental element - a primordial cyst.
(A) (B) (C)

19. Periapical (Radicular) Cyst
 Most common odontogenic cyst and results from
inflammation secondary to caries or other entities.
 The peak prevalence of this asymptomatic cyst occurs
between the 4th and 6th decades of life.
 Typically, infection spreads to the apex (root) of the
tooth, leading to secondary apical periodontitis,
granuloma, or abscess and finally cyst formation.
 The cyst appears as a round or pear-shaped, well-
defined radiolucent lesion with sclerotic borders.
 Most periapical cysts are less than 1 cm in diameter.
 It is important to note that radiology cannot always
help distinguish a granuloma from a cyst.

20. 2. Periapical cyst in a 60-year-old woman. Computed tomographic (CT) scan (a) and
coronal reformatted CT image (b) demonstrate a radiolucent lesion (arrows)
surrounding the apex of a molar. A defect with dental filling (arrowhead) is present
within the crown of the tooth. (3) Periapical cyst in a 40-year-old man. Panorex image
demonstrates a circular radiolucent lesion (arrow) at the apex of a molar. Note the
dental filling (arrowhead) from a prior procedure.

21. Follicular (Dentigerous) Cyst
 This is the most common developmental odontogenic
cyst.
 The lesion forms around the crown of an unerupted
tooth (commonly the third molar) and is typically
diagnosed in patients between 30 and 40 years of age.
 The enamel epithelium surrounding the crown
proliferates, and fluid collects between the layers.
 Therefore, identifying the crown of a tooth projecting
into the cystic cavity is pathognomonic .
 The cyst appears radiologically as a well-demarcated
radiolucent lesion attached at an acute angle to the
cervical area of an unerupted tooth.
 The border of the lesion may be radio-opaque.

22. Unlike radicular cysts, a
follicular cyst may become
extremely large, often
distorting the roots of adjacent
teeth and remodeling the
mandible.
However, the cortical bone is
usually preserved.
A few cases of ameloblastic
transformation of a follicular
cyst in patients under 40 years
of age have been reported.
Follicular cyst in a 40-year-old man.
Coronal reformatted CT image reveals a
cystic lesion with an unerupted tooth in
the right molar region (arrow). The
crown of the tooth is contained within
the lesion.

23. Odontogenic keratocyst cyst
(OKC)/Primordial Cyst
 These may follow cystic degeneration of the enamel
organ before the tooth is formed, so that the cyst
replaces the tooth, but they may also arise from
ectopic odontogenic epithelium.
 If there is a normal complement of teeth then the cyst
is assumed to have replaced a supernumerary tooth.
 Primordial cysts are more common in young men, but
may be seen at all ages.
 They are slow-growing but may reach a very large size
and may occupy the entire ascending ramus.

24.  OKCs develop from the dental
lamina, which is found
throughout the jaw and
overlying alveolar mucosa and is
lined by stratified keratinizing
squamous epithelium.
 Unlike follicular cysts, these can
expand cortical bone and erode
the cortex.
 Fortunately, malignant
transformation of these lesions is
rare.
Image (above), OKCs in a 22-year-old man. Panoramic reformatted CT image demonstrates
cystic lesions with well-demarcated borders (arrows) within the mandible. There is no
evidence of adjacent tooth root erosion. Note the slight expansile change and remodeling of
the mandibular cortex without bone destruction. Image (below) OKC in a 41-year-old man
with basal cell nevus syndrome (Gorlin-Goltz syndrome). Contrast – enhanced CT scan shows
multiple cysts (arrows) in the mandible. Cystic lesions (arrowheads) are also identified within
the maxilla. CT also demonstrated a calcified falx and large frontal sinuses, findings that helped
establish the diagnosis (Not included in these images).

25. A B
C D
16-year-old girl with
mandibular odontogenic
keratocyst.
A, Panorex image shows
large lucent lesion with
scalloped border (arrows).
B, Sagittal T1-weighted
MR image shows
expansile lesion (asterisk)
with intermediate signal
intensity in posterior
mandible.
C, Sagittal contrast-
enhanced T1- weighted
MR image shows
peripheral rim like
enhancement of
lesion around third molar.
D, Axial conventional T2-
weighted MR image shows
inhomogeneously
hyperintense expansile
lesion (asterisk) with areas
of low signal intensity in
left posterior mandible

26. Solitary Bone Cyst (Traumatic,
Simple, Hemorrhagic Bone Cyst)
 A solitary bone cyst results from trauma, which leads
to intramedullary hemorrhage and subsequent
resorption.
 These pseudocysts are most commonly located in the
posterior marrow space of the mandible and appear
slightly irregular with poorly defined borders.
 They have a characteristic scalloped superior margin
extending between the roots of adjacent teeth.
 In addition, the mandibular cortex may be thinned
secondary to osseous expansion.

27. Solitary (hemorrhagic)
bone cyst in a 25- year-old
woman. Coronal
reformatted CT image
demonstrates a cystic
lesion (arrows) within the
mandibular body. The
mandibular cortex is
thinned. Note the normal
tooth (arrowhead) within
the lesion, a finding that
helps distinguish the cyst
from radicular or other
odontogenic cysts.

28. Residual Cyst
Residual cyst is a generic term for any cyst that
remains after surgical intervention.
Thus, most residual cysts are periapical
(radicular) cysts.

29. Static Bone Cavity (Stafne Cyst)
 A static bone cavity
appears as an ovoid or
round, well-defined
radiolucent lesion within a
cortical defect on the
medial surface of the
posterior mandible.
 Typically measuring less
than 2 cm, the cavity of
this pseudocyst is usually
filled with fat but may also
contain submandibular
salivary gland tissue
Static bone cavity (Stafne cyst) in a
35-year-old man. CT scan reveals a
cortical defect (arrow) in the lingual
surface of the right mandibular
angle, a finding that does not
represent a true cyst.

30. Solid Benign Lesions;
Primary Odontogenic Tumors
Odontoma
 Odontoma is the most common odontogenic tumor of
the mandible, accounting for approximately 67% of all
cases.
 The lesion consists of various tooth components,
(including dentin and enamel) which have developed
abnormally to form a “hamartomatous” lesion.
 Nearly 50% of odontomas are associated with an
impacted tooth and most are diagnosed during the
second decade of life. However, odontomas may
develop before or after tooth eruption.

31.  Forming between the roots of teeth, the tumor is initially
radiolucent but evolves to contain small calcifications,
eventually, forming a radio-opaque mass with a lucent rim.
 The WHO classification scheme further subdivides
odontomas into compound and complex types, depending
on their composition compared with normal teeth
 Compound odontomas have radiographically identifiable
tooth components (abortive teeth), whereas complex
odontomas contain multiple masses of dental tissue with
amorphous calcifications.
 Most odontomas can cause impaction or resorption of
adjacent teeth.

32. Compound odontoma in a
28-year-old woman.
Panorex image
demonstrates a focus of
radiopaque enamel
surrounded by a thin
radiolucent
follicle(arrow). Note the
impacted tooth
(arrowheads) deep to the
odontoma.

33. Ameloblastoma.
 Is a locally invasive, benign neoplasm arising from
enamel-forming cells of the odontogenic epithelium
that do not regress during embryonic development.
 This lesion typically presents in the third to fifth
decades of life.
 Approximately 75% occur in the mandible, usually
involving the posterior mandible, often around the
third molar, the other 25% occur in the maxilla.

34.  It is a slow-growing tumor allowing considerable mandibular
expansile remodeling often associated with the crown of an
unerupted or impacted tooth.
 The tumor often has a somewhat bubbly appearance and
may erode adjacent tooth roots, although it is considered a
benign lesion.
 Malignant transformation is rare, occurring in approximately
1% of cases.
 There is a high likelihood of recurrence if the tumor is not
adequately resected.

35.  CT shows a low-attenuating lesion without matrix
mineralization and typically shows expansile remodeling
and cortical thinning.
 If extraosseous extension occurs, contrast enhanced images
show soft-tissue enhancement mixed with low-attenuating
regions.
 MRI, ameloblastoma has mixed signal intensity on T1- and
T2-weighted images: typically overall low signal intensity on
T1-weighted images and high signal intensity on T2-
weighted images.
 Contrast-enhanced imaging may show enhancing mural
nodules and septations.

36. A B C
D E
30-year-old woman with
ameloblastoma.
A, Panorex image shows large lytic
lesion (arrows) in left mandible. B and C,
Coronal (B) and axial (C) CT images
through mandible reveal show
multilobulated lytic lesion (asterisk) in
posterior left mandible with expansile
remodeling, scalloped borders and
cortical thinning.D, Photograph of gross
specimen showsbreakthrough of
ameloblastoma on lingual side.
E, Specimen radiograph shows
findingscorresponding to D.

37. 47-year-old man with ameloblastoma of maxilla.
A, Sagittal T1-weighted MR image shows heterogeneously low-intensity lesion (asterisk) in
right maxillary sinus largely isointense to skeletal muscle.
B and C, Axial fast spin-echo T2-weighted MR images show multiloculated
heterogeneously hyperintense lesion (asterisk) and expansile remodeling of sinus walls.
A B C

38.  However, only histopathologic findings can help
determine benignity and the absence of carcinomatous
change .
 Although multiple subtypes of ameloblastomas exist,
most cannot be distinguished with radiology alone.
 Histopathologic analysis must provide the definitive
subtype diagnosis of each lesion, with the exception of
desmoplastic ameloblastoma.
 Distinguishing features of this subtype include multiple
coarse internal calcifications with significant
surrounding cortical destruction.

39. Desmoplastic ameloblastoma in a 30-year-old woman.
CT scan (a) and contrast-enhance T1-weighted magnetic resonance (MR) image
(b) demonstrate an expansile enhancing lesion within the right mandibular body
(arrows) that causes significant buccal cortical destruction.

40. Odontogenic Myxoma
 Odontogenic myxoma is clinically and radiographically
indistinguishable from ameloblastoma, appearing as a
multiloculated radiolucent lesion with internal osseous
trabeculae.
 This rare tumor typically manifests in the second or
third decade of life

41. Calcifying Epithelial Odontogenic Tumor
 Calcifying epithelial odontogenic tumor (Pindborg
tumor) is composed of epithelial cells in a fibrous
stroma.
 The tumor typically appears radiolucent with scattered
calcified components.
 Most tumors are located in the premolar or molar
region of the mandible and are associated with the
crown of an impacted tooth.

42. Cementoblastoma
 Cementoblastoma is a true neoplasm (rare) of
cementum that typically occurs in patients under 25
years of age.
 Usually found in association with the apex of the first
molars, the lesion appears as a round, well demarcated
opaque sunburst mass with a thin radiolucent rim.
 The periodontal ligament space becomes obscured by
the lesion.

43. Ameloblastic Fibroma
 Composed of epithelium representing enamel and
embryonic connective tissue, ameloblastic fibroma
typically appears as a well-defined, pericoronal
radiolucent lesion.
 Most are multiloculated and associated with impacted
teeth, often within the posterior mandible.
 Although ameloblastic fibromas do not represent a
variant of ameloblastomas, they can appear
radiologically as unilocular ameloblastoma

44. Ameloblastic fibroma in
a 15-yearold boy.
Coronal reformatted CT
image reveals a slightly
lobulated, well-defined
expansile lesion
(arrows) within the
right mandibular body.
Note the prominent
internal calcifications.

45. Adenomatoid Odontogenic Tumor
 Is a rare tumor typically diagnosed in the second decade
of life, with the majority found in girls and young women,
in addition, approximately 70% are found in the maxilla.
 The tumors appear as well demarcated radiolucent lesions
with varying amounts of punctate calcifications and can
displace or prevent the eruption of teeth.
 If attached to a tooth, the lesions are found more apically
on the root than are dentigerous cysts.
 The characteristic imaging findings, along with appropriate
patient demographic information, can help narrow the
differential diagnosis.

46. Adenomatoid odontogenic
tumor in a 14-year-old boy. CT
scan demonstrates a
unilocular radiolucent lesion
with a linear calcification
(arrow) centered between the
lateral incisor tooth and
canine tooth. Note that the
impacted tooth (arrowhead) is
unaffected, a finding that
indicates that the tumor
developed after completion of
odontogenesis.

47. Osteochondroma
 It is the most common bone tumor and has cortical and
medullary continuity with the host bone.
 This is a developmental lesion that typically is painless,
where pain suggests a complication such as a fracture,
bursitis, associated nerve or blood vessel compression, or,
rarely, malignant transformation.
 Malignancy should be considered if the lesion continues to
grow or if a cartilaginous cap more than 2 cm thick is found
in a skeletally mature patient.
 Malignant transformation occurs in approximately 1% of
solitary osteochondromas and 3–5% of patients with
multiple hereditary exostosis.

48.  Treatment of osteochondroma is specific to each case.
 Small asymptomatic osteochondromas can be observed,
but larger symptomatic lesions may have to be resected.
 The overall recurrence rate after resection is 2%.
 D/D is chondrosarcoma but chondrosarcoma typically
undergoes cortical disruption and has a thick cartilaginous
cap.

49. 52-year-old woman with osteochondroma. Anteroposterior (Left) and
oblique (Right) collimated radiographs show exophytic lesion (arrow)
extending from mandibular angle with cortical and medullary continuity
with host bone.

50. Giant Cell Tumor
 Most giant cell tumors occur in patients 20–50 years.
 Five percent of these tumors are malignant, typically
secondary to radiation of a benign giant cell tumor.
 Patients may present with pain, local swelling and
limited range of motion of the adjacent joint.
 The most common locations of giant cell tumors in
decreasing order are the distal femur, proximal tibia,
distal radius, sacrum, and proximal humerus.

51.  CT scan will show a well-
defined lytic with
expansile remodeling and
cortical thinning.
 On bone scan may show
increased radiotracer
activity in periphery with
a central area of minimal
activity (Doughnut sign).
59-year-old man with giant cell tumor
and progressive left jaw discomfort and
difficulty chewing for 10 years. Axial CT
image through left mandibular condyle
shows well-defined lytic lesion
(asterisks) in condyle and expansile
remodeling and cortical thinning.

52. Primary Non-odontogenic Tumors
Ossifying Fibroma (cemento-ossifying or cementifying)
 Contains fibrous tissue with varying amounts of bony trabeculae.
 Typically diagnosed during the third and fourth decades of life.
 Majority of these tumors occur within the posterior mandible.
 The encapsulated, well-circumscribed lesion can appear
radiolucent, radiopaque or with mixed opacity depending on the
degree of calcification.
 With maturation, the lesion become more radiopaque.
 Although the lesion is similar in appearance to fibrous dysplasia
its radiolucent boundary allows some distinction.

53.  Juvenile ossifying fibroma
is an aggressively growing
destructive variant of the
tumor, typically occurring
in boys under 15 years of
age.
 The lesion has been
reported to arise within
both the mandible and
paranasal sinus regions,
exhibiting rapid growth.
Ossifying fibroma in a 33-year-old
woman. CT scan reveals a circular,
partially calcified lesion (arrow) within
the mandible. Note the internal
ground-glass calcifications.

54. Periapical Cemental Dysplasia
 Forms from proliferation of connective tissue found within the
periodontal membrane.
 The majority of lesions occur in women during the fourth and
fifth decades of life.
 Most lesions are multifocal and occur between the mandibular
canine teeth.
 They begin as a well-circumscribed radiolucent lesion at the apex
of the tooth and progressively change into a radio-opaque mass
surrounded by a radiolucent border.
 Simple bone cysts may develop within these lesions.
 Florid cemental dysplasia (florid cemento-osseous dysplasia) is
the diffuse form of periapical cemental dysplasia and involves the
entire mandible.

55. Periapical cemental
dysplasia in a 48-
year-old woman.
Occlusal radiographs
demonstrate a well-
defined radiopaque lesion
(arrows) at the apex of a
tooth. The advanced
degree of calcification
indicates maturity of the
lesion.

56. Solid Malignant Lesions
Primary Odontogenic Tumors
 The majority of carcinomas are secondary to invasion
from the surrounding mucosa.
 Primary carcinomas include odontogenic carcinoma,
primary intraosseous carcinoma and malignant
ameloblastoma.
 Some cases of carcinomatous transformation of OKCs
have also been reported.

57. Odontogenic Carcinoma
 Odontogenic carcinoma is a rare, aggressive
intraosseous lesion consisting of poorly differentiated
epithelial and clear cells.
 The lesion appears as a diffuse, “honeycomb”- like
radiolucent lesion with surrounding cortical
destruction.
 Because of the high rate of recurrence, prognosis is
poor for patients with this tumor.

58. Ameloblastic Carcinoma/Malignant
Ameloblastoma
 Ameloblastomas of the mandible rarely become malignant;
however, the potential for malignant transformation does
exist.
 Although there is some controversy regarding terminology,
most authors advocate the term ameloblastic carcinoma for
tumors with typical cytologic findings of malignancy with or
without metastasis.
 The term malignant ameloblastoma should be restricted to
an ameloblastoma that is histologically benign but
demonstrates evidence of metastasis.
 It is very difficult to distinguish these tumors from benign
ameloblastomas at imaging alone and histopathologic analysis
is required for definitive diagnosis.
 However, aggressive features such as cortical destruction,
extraosseous extension and extensive solid components may
suggest malignant potential.

59. Ameloblastic carcinoma in a 17-year-old boy. (a) CT scan
(bone windowing)shows soft-tissue mass (arrows) with
adjacent bone destruction. (b) Axial contrast enhanced
T1-weighted MR image demonstrates the enhancing soft-
tissue mass (arrows). (c) High-power photomicrograph (H-
E stain) reveals innumerable ameloblastic cells with
reversed polarity and nuclear pleomorphism (arrows).

60. Primary Nonodontogenic Tumors
 Various nonodontogenic solid malignant tumors occur in the jaw,
which is not typically the primary site of diagnosis.
 Sarcomas such as osteosarcoma chondrosarcoma, fibrosarcoma,
an leiomyosarcoma can cause both osteolytic and osteoblastic
lesions.
 A symmetrically widened periodontal membrane in a single
tooth may be the earliest radiologic indication of osteogenic
sarcoma.
 Although mucoepidermoid carcinoma is typically associated with
minor salivary glands of the buccal mucosa, a primary mandibular
form occasionally occurs.

61. Osteosarcoma in a 41-year-old man. (a) CT scan reveals osteoblastic changes
(arrows) within the right mandibular body. Note the abnormal soft-tissue ossification
(arrowhead). (b) Contrast-enhanced T1-weighted MR image demonstrates an ill-
defined lesion (arrow) arising from periosteum. Note the decreased marrow signal
intensity (arrowhead) involving the entire right mandibular body.

62. Mucoepidermoid carcinoma in a 66-year-old man. CT scan (soft-tissue windowing)
(a) and sagittal reformatted CT image (bone windowing) (b) show a large soft-tissue
mass (arrows) that has destroyed the posterior body of the left mandible and extends
into the buccal space. Note the invasion of the mandibular canal (arrowhead).

63.  Lymphoma and leukemia also have no pathognomonic findings
and typically manifest as ill-defined osteolytic lesions of varying
size.
 Patients with multiple myeloma may present with “chin
numbness” due to involvement of the inferior alveolar nerve.
 Multiple myeloma may also occur with or without the typical
“punched-out” lesions.
 The ovoid radiolucent lesions will demonstrate no evidence of
expansion or adjacent bone reaction but may erode the cortex .

64.  Multiple myeloma typically is fatal 1–5 years after diagnosis.
 Sclerosis may be seen after treatment.
 MRI is the most sensitive imaging modality which shows
multiple lesions typically having intermediate to low signal
intensity compared with bone marrow on T1-weighted images
and high signal intensity on T2-weighted and STIR images
 If bone scintigraphy is performed, the findings may be normal, or
increased (as a result of hyperemia) or decreased (as a result of
replacement of marrow cells) activity may be found.

65. Multiple myeloma in a 67-year-old man. (a) Panoramic reformatted CT image
demonstrates sclerotic (arrow) and lytic (arrowhead) lesions in the mandible.
(b) Axial T1-weighted MR image shows loss of the marrow fat within the
right mandibular angle (arrow) and mandibular foramen (arrowheads).
A collimated view of the
mandible and lateral skull
radiograph showing multiple
punched-out lytic lesions in
the skull and posterior
mandible

66. Metastasis
 Often involves the mandible.
 Although the lesions are typically radiolucent with ill-
defined borders, some blastic lesions such as prostate
metastasis may occur.
 The most common sites of origin include the kidneys,
lungs and breasts; however, other primary sites have
also been documented .
 Because of the increased marrow vascularity, the
posterior body and angle are most commonly affected.
 Metastasis to the mandible is four times more
common than metastasis to the maxilla.
 Identification of these lesions with accurate
identification of the primary site is crucial, since
approximately 30% of jaw metastases originate from
an occult primary lesion.

67. A B
C D
50-year-old man with left-
sided jaw pain for 2 weeks
and left lower facial
numbness and anterior left
chin tingling for several
months. Diagnosis was
metastatic adenocarcinoma.
A, Panorex image shows
loss of superior cortical
margin (white arrow) and
associated subtle lytic lesion
(black arrow) in left
mandibular angle.
B, Bone scans show focus of
increased scintigraphic
activity (arrows) in left
mandibular angle.
C, Coronal CT image near
angle of mandible shows
lytic lesion (asterisk).
D, Axial CT image through
mandible shows lytic lesion
(asterisk)

68. 77-year-old man with several-month history of jaw aching. Metastatic Melanoma; Upper row, Coronal
(Left) and axial (Middle) CT images show large lytic lesion (arrows) in right mandibular ramus with
expansile cortical remodeling and extraosseous extension. No internal matrix is present. Axial T1-weighted
(Upper row, right), Lower row, FLAIR (Right), contrast-enhanced fat-saturated T1-weighted (Middle), and
fast spin-echo T2-weighted (Left) MR images show expansile enhancing intermediate-signal-intensity
lobulated mass (asterisk) involving right mandibular ramus and right masticator space.

69. Metastatic
hepatocellular
carcinoma
in a 61-year-old man.
Contrast-enhanced
CT scan demonstrates
an expansile,
osteolytic mass
(arrows) within the
right mandibular
body.

70. Vascular and Neurogenic Lesions
Central Giant Cell Granuloma (Giant Cell Reparative Cyst)
 Is believed to be a single lesion in a spectrum of altered
vascular and reactive responses within bone.
 The lesion most frequently occurs in girls and young
women during the second and third decades of life.
 The majority of these lesions are found in the anterior
mandible. Initially, a giant cell reparative cyst manifests
as a small, unilocular radiolucent lesion that can mimic
an odontogenic cyst.
 With development however, the lesion becomes
multilocular, exhibiting a honeycomb appearance.

71.  Tiny bone septa are present traversing the lesion.
 There may be evidence of expansion, root resorption, and
erosion or remodeling of the cortex.
 In addition, the lesion may cross the midline of the
mandible.
 The differential diagnosis includes brown tumors of
hyperparathyroidism, which can appear radiologically and
histologically identical to giant cell reparative cysts.
 However, the patient’s age and laboratory test results
should easily help distinguish between these two entities.

72. Central giant cell granuloma
in a 34-year-old man. (a) CT scan
(bone windowing) demonstrates
a cystic lesion (arrows) within the
mandible. Note the erosion of
the mandibular cortex.
(b) Photograph of the gross
resected specimen shows
multiple cystic cavities (arrows).
Photomicrography
with H-E stain revealed
multinucleated giant cells within
the lesion

73. Arteriovenous Malformations
 Are abnormal, direct communications between arteries and
veins.
 Although AVMs are uncommon inthe jaw, they may occur
within the ramus and posterior mandibular body.
 Identification of an AVM is important owing to the
potential for fatal hemorrhage after tooth extraction.
 At radiography, the multiloculated lesions are cystic in
appearance secondary to adjacent bone resorption.
 Angiography may be necessary to help confirm the
diagnosis and for treatment planning.

74. AVM in a 28-year-old man. (a) Contrast-enhanced CT scan reveals multiple
dilated and tortuous vessels (arrow) within the right masseter muscle. Note the
abnormal enhancement (arrowhead) within the marrow of the mandible. (b) Axial T1-
weighted MR image demonstrates a slightly expansile lesion (arrow) within the right
mandibular angle and body. Multiple flow voids are present within the right masseter
muscle. Note the loss of normal fatty marrow (arrowhead) within the mandible

75. Central Hemangioma, Neurofibroma,
and Schwannoma
 Central hemangioma, neurofibroma, and schwannoma are
usually well-defined soft-tissue structures with well-
corticated margins.
 However, a central hemangioma may also manifest as a
multilocular radiolucent lesion.
 There is often displacement of adjacent structures with
root resorption.
 Widening of the inferior alveolar canal may be the only
finding to indicate a neurofibroma

76. Metabolic Abnormalities
 Metabolic abnormalities may cause lesions in the
mandible that appear similar to lesions occurring
elsewhere in the body.
 Such systemic disorders include osteoporosis,
osteomalacia, renal osteodystrophy and osteitis
fibrosa cystica (hyperparathyroidism).
 Although some metabolic abnormalities appear similar
to primary lesions such as fibrous dysplasia or Paget
disease, the patient’s history alone usually allows the
correct diagnosis to be made.

77. Renal osteodystrophy in
a 75 year-old man.
CT scan reveals diffuse
sclerotic changes
(arrows) throughout the
entire mandible.

78. Tumor like Lesions
 Congenital lesions, developmental anomalies, and
other tumorlike conditions such as condylar hypoplasia
and torus mandibularis may occur in the mandible.
 Gardner syndrome (colorectal polyposis, soft-tissue
tumors, and skeletal abnormalities) is a hereditary
condition that manifests with multiple osteomas, also
arising within the mandible.
 These well-defined radiopaque lesions are often
associated with multiple impacted and supernumerary
teeth.

79.  Epulis fissuratum is a diagnosis that is well known to
dentists but often unfamiliar to general radiologists.
 The lesion consists of mucosal hyperplasia resulting from
chronic low-grade trauma induced by a denture flange.
 Congenital epulis, a rare tumor seen in neonates, differs
from epulis fissuratum in that it manifests as
pedunculated, alveolar mucosal lesions.
 Fibrous dysplasia and osteitis deformans (Paget disease)
appear the same in the mandible as they do in other parts
of the body.

80.  Osteoradionecrosis may develop months to years following
radiation therapy.
 Radiographic findings vary depending on radiation dose
and duration.
 As with bone in other sites, endothelial cell death and
thrombosis of vessels occur, leading to periosteal fibrosis
and cell necrosis.
 Areas of osteoradionecrosis contain both sclerotic and lytic
components with poorly defined borders and enlarged
trabecular spaces.
 Sequestered bone is often identified within the region.

81. Torus mandibularis in a 35-yearold
man. CT scan shows bilateral exostosis
(arrows) in the lingual aspects of the
mandible
Gardner syndrome in an 80-yearold
man. Panorex radiograph demonstrates
multiple osteomas (arrows) throughout the
mandible. Note the osteoma within the
right maxilla (arrowhead).

82. Epulis fissuratum in a 22-year-old woman.
(a) CT scan shows calcification and soft-tissue thickening (arrow) in the lingual aspect of
the right mandible.
(b) Intraoral photograph reveals a lump (arrow) in the gingiva.

83. Fibrous dysplasia in a 28- year-old man.
Contrast-enhanced CT scan
demonstrates an expansile lesion
containing numerous unorganized bone
trabeculae (arrow) within the left
mandibular body.
Osteoradionecrosis in a 56-year-old man
with a history of radiation therapy for
oropharyngeal squamous cell carcinoma.
Panoramic reformatted CT image shows ill-
defined osteolytic lesions (arrows) within the
left mandibular body, findings that represent
osteonecrosis. In addition, a diffusely sclerotic
region (arrowheads) is identified within the
right mandibular body, a finding that
represents osteitis.

84. Other Lesions; Infectious Lesions
Apical periodontitis
 Apical periodontitis encompasses the spectrum of periapical
cysts, granulomas and abscesses.
 Most of these lesions are caused by dental caries and result in
irreversible pulpitis.
 As mentioned earlier, apical cyst and granuloma are difficult
to distinguish from each other at imaging.
 A thickened periodontal ligament space is the earliest sign for
identifying these lesions in their cystic form.
 If the lesion progresses to an apical abscess, contrast-
enhanced imaging will reveal an enhancing rim.

85. Periapical and perimandibular abscess in a 10-year-old boy.
(a) Contrast-enhanced CT scan demonstrates a rim-enhancing fluid collection (arrows)
within the perimandibular soft tissues.
(b) Oblique coronal reformatted CT image reveals a periapical abscess (thick arrow)
within the mandibular body and a fistula (arrowhead) that extends to the lingual
surface. Note the cavity (thin arrow) within the crown of the tooth.

86. Osteomyelitis
 Infection of both the bone and marrow of the mandible, is
rare in healthy individuals due to early administration of
antibiotics.
 Its radiographic appearance ranges from acute or chronic
suppurative to sclerosing osteomyelitis.
 Acute suppurative osteomyelitis usually demonstrates no
imaging findings in the early stages, whereas chronic lesions
demonstrate a variety of bone reactions including radiolucent
and radio-opaque areas.
 Low-grade infections can cause sclerosing osteomyelitis, in
which bone is deposited along the osseous cortex and
trabeculae .

87. Possible causes of mandibular osteomyelitis include direct
extension of pulpal infection, acute exacerbation of a
periapical lesion and a surgical procedure or penetrating
trauma.
 Associated soft-tissue abnormalities (including haziness or
obliteration of the fat planes) help differentiate infection
from neoplasia, which typically sharply distorts fat planes.
The earliest radiographic osseous change is indistinctness of
the cortex, but this change generally is not evident on
radiograph for 1–2 weeks after the onset of infection.
Subsequent osseous changes include permeative osseous
destruction and periosteal reaction.

88.  Sequestra, representing foci of necrotic bone, are more
typically associated with chronic osteomyelitis and are
well visualized at CT.
 The sequestra typically contain bacteria and serve as a
source of chronic infection.
 Facial and mandibular radiography is relatively
insensitive for identification of acute osteomyelitis.
 CT is more sensitive and contrast-enhanced MRI is
much more sensitive for early disease.
 T1-weighted MR images show a confluent region of
low signal intensity, and fluid-sensitive images show
increased signal intensity in the bone and soft tissue
abscess.

89.  Fluid-sensitive sequences are overly sensitive for
osteomyelitis and the images thus must be interpreted with
the T1- weighted findings.
 Contrast-enhanced MR images reveal a rim of
enhancement around the abscess and within the bone.
 Nuclearmedicine studies used to evaluate for osteomyelitis
primarily include three-phase bone scintigraphy and a
combined WBC scan.
 Three-phase bone scans typically show increased activity in
all three phases if the patient has acute osteomyelitis

90. 73-year-old man with
osteomyelitis, known case
of DM diabetes presenting
with persistent right-sided
jaw pain since extraction of
two right posterior
mandibular teeth 6 months
earlier.
A, Panorex reconstruction
of mandibular CT scan
shows destruction of
superior cortex (arrows) of
right mandibular body with
associated sclerosis and
gas. B–D, Axial (B and C)
and collimated coronal (D)
CT images show lytic
destructive changes
(asterisk, B) of right
mandibular body with
lamellated periosteal
reaction (arrows, D).
A B
C D

91. Blood-flow
(E), blood-
pool (F), and
delayed
anterior (G)
and lateral
(H) images
from three-
phase
bone scan
show
increased
radiotracer
uptake in right
mandibular
ramus in all
three phases
E F
G H

92. Chronic osteomyelitis in a 47-yearold
man. CT scan reveals an osteolytic lesion
(arrow) containing a bony sequestrum
(arrowhead) within the left mandibular
body
Sclerosing osteomyelitis in a 10-year-old
boy. CT scan shows diffuse sclerotic changes
with expansion of the left mandibular body
(arrows). Note the diffuse soft-tissue swelling
(arrowheads).

93. 38-year-old man with
fever, facial swelling and
tenderness as a result of
necrotizing fasciitis.
A, Clinical photograph at
presentation shows
inflammatory changes
involving right lower
lateral teeth and
purulent gingival
discharge (arrow).
B–D, Axial CT images
show foci of air in
crescentic subfascial fluid
collections, associated
inflammatory
changes in subcutaneous
and intermuscular
regions, and skin
thickening.
A B
C D

94. Conclusions
 The teeth and their support structures are commonly
included on head and neck images.
 When normal variants or pathologic conditions are
identified at CT, radiologists may provide additional
assistance by identifying these conditions and including
them in their report.
 The ability to recognize and proper characterization of
jaw abnormalities essential to ensure appropriate
patient care and reduce morbidity.
 Thus imaging plays a key role in the characterization of
a variety of jaw lesions, and radiologists must be
familiar with these imaging findings.

95. References
• Textbook of Radiology and Imaging- David Sutton.
• Imaging Characteristics of Benign, Malignant, and
Infectious Jaw Lesions: A Pictorial Review-Kathleen
A. Meyer et al.
• Radiologic and Pathologic Characteristics of Benign
and Malignant Lesions of the Mandible-Brian.
• Teeth: What Radiologists Should Know- Meir H.
Scheinfeld et al.Dunfee et al.