1. The document discusses differential diagnosis of pericoronal radiolucencies, which are lesions that cause radiolucency in the coronal region of teeth. 2. It describes common conditions that can present as pericoronal radiolucencies such as follicular spaces, dentigerous cysts, unicystic ameloblastoma, and ameloblastic fibroma. 3. For each condition, it provides details on prevalence, location, symptoms, imaging features, and management considerations to help differentiate between potential diagnoses.

2. 5 DIFFERENTIAL DIAGNOSIS
OF PERICORONAL
RADIOLUCENCIES
MUHSINA T
FINAL YEAR PART 1

3. CONTENTS
• INTRODUCTION
• PERICORONAL RADIOLUCENCIES
• DIFFERENTIAL DIAGNOSIS
• CONCLUSION
• REFERENCE

4. INTRODUCTION
• Pericoronal radiolucencies - lesions which cause radiolucency in the
coronal region of the teeth
• The crowns of unerupted teeth are surrounded by dental follicle,
pathological changes can occur in these follicles
• Is the most common finding during routine radiographic examination
associated with impacted, embedded, and unerupted tooth.

5. PERICORONAL RADIOLUCENCIES
• PERICORONAL OR FOLLICULAR SPACE
• UNICYSTIC (MURAL) AMELOBLASTOMA
• AMELOBLASTOMA
• ADENAMATOID ODONTOGENIC TUMOR
• CALCIFYING ODONTOGENIC CYST OR TUMOR
• AMELOBLASTIC FIBROMA

6. RARITIES
• Ameloblastic variants
• Calcifying epithelial odontogenic
tumor
• Envelopmental primordial cyst
• Ewings sarcoma
• Extra follicular dentigerous cyst
• Follicular primodial cyst
• Odontogenic carcinoma
• Odontogenic fibroma
• Odontogenic keratocyst
• Odontogenic myxoma
• Odontoma in pericoronal location
• Ossifying fibroma

7. 5 DIFFERENTIAL DIAGNOSIS OF
PERICORONAL RADIOLUCENCIES

8. PREDO
MINT
GENDER
PEAK
AGE
(YEAR)
MOST
FREQUENT
JAW
INVOLVED
MOST
FREQUENT
AREA OF
JAW
INVOLVED
MOST
FREQUENT
TOOTH
INVOLVED
SIGNS OR
SYMPTOMS
RECURRENCE
FOLLICULA
R SPACES
DEVELOPI
NG TEETH
IMPACTED
TEETH
_
M~F
4-12
OVER
18 Mandible
Posterior Mandibular
3rd molar
None
Delayed
eruption of
tooth
Recurs as cyst or
ameloblastoma
DENTIGER
OUS CYST
M~F OVER
18
mandible posterior Mandibular
3rd molar
Delayed
eruption of
tooth
Swelling,
asymmetry
Recurs as cyst or
ameloblastoma

9. PREDO
MINT
GENDER
PEAK
AGE
MOST
FREQUENT
JAW
INVOLVED
MOST
FREQU
ENT
AREA
OF
JAW
INVOLV
ED
MOST
FREQUENT
TOOTH
INVOLVED
SIGNS OR
SYMPTOMS
RECURRENCE
ADENOMA
TOID
ODONTOG
ENIC
TUMORS
F:M 2:1 10 – 21
(average
16.5)
Maxilla Anterior
(90%)
Maxillary
canine (60%)
Delayed eruption
of tooth, Swelling
asymmetry
Unusual
AMELOBLA
STIC
FIBROMAS
M~F 70%
under
20
(average
14 –
15.5)
Mandible posterior Mandibular
molar and
premolar
Delayed eruption
of tooth,
advanced
Swelling,
asymmetry
Unusual

10. PREDO
MINT
GENDE
R
PEAK
AGE
MOST
FREQU
ENT
JAW
INVOL
VED
MOST
FREQUE
NT
AREA
OF JAW
INVOLV
ED
MOST
FREQUEN
T TOOTH
INVOLVED
SIGNS OR
SYMPTOMS
RECURRE
NCE
UNICYSTIC
(MURAL)
AMELOBLAST
OMA
M~F 85%
under 30
( average
21 yrs)
mandibl
e
posterior Mandibular
3rd molar
Delayed eruption of
tooth
Swelling, asymmetry
occasional
AMELOBLAST
OMA
M~F Average
38.9
Mandibl
e
posterior Mandibular
3rd molar
Delayed eruption of
tooth, Swelling
asymmetry
Significant

11. 1. PERICORONAL OR FOLLICULAR
SPACE

12. PERICORONAL OR FOLLICULAR SPACE
• The follicle appears on radiograph as a homogenous radiolucent halo.
• Halo - thin outer radiopaque border, representing compact bone that
is continuous with the lamina dura
• The radiolucent halo merges with the periodontal ligament space
• Halo varies in depth because of the varying thickness of the follicles
and the accumulation of fluid

14. • The unerupted maxillary canines frequently have enlarged follicular
spaces , especially when their eruption has been delayed
• Some children have generalized enlargement and hyperplasia of their
follicular spaces
• Hyperplastic dental follicles have been reported with rough
hypoplastic amelogenesis imperfecta and in Lowe syndrome

15. Hyperplastic dental follicle

16. Guidelines
•
1. When an asymptomatic follicular radiolucency becomes
approximately 2.5cm in diameter and surrounding cortical plate is
poorly defined, disease is strongly suggested
2. If the coronal space reaches 2.5 mm in width on the radiograph ,
this is presumptive evidence that fluid is collecting within the
follicle and pathoses is present in 80% cases

17. MANAGEMENT
• The absence of clinical symptoms ,it is advisable to radiograghically
examine equivocally enlarged or enlarging follicles at least every 6
months
• If eruption delayed , a dentigerous cyst or another pericoronal
pathological condition must be considered, and surgical intervention
is indicated

18. 2. DENTIGEROUS CYST

19. DENTIGEROUS CYST
• Synonym – follicular cyst
• Most common odontogenic cyst after the
radicular cyst
• Associated with the crowns of unerupted or
developing teeth
• The etiology of cystic formation is unknown
• Classified as developmental cyst

20. Clinical features
• Most common pericoronal radiolucency
• Incidence is equal in both sexes
• The most frequently affected-
mandibular 3rd molars > the maxillary canines >
the mandibular premolars > and the maxillary 3rd
molars
• Commonly associated with maxillary mesiodens
(90%)

21. • Size - less than 2 cm diameter to massive expansion
• May cause painless enlargement of the jaws and facial asymmetry.
• The slowly expanding cyst erodes cortical plates,on palpation reveals
a rubbery , fluctuant, nonemptiable mass
• Aspiration yields a straw colored, thin liquid with Cholesterol crystals.

22. • Usually painless, delayed eruption of tooth may be the clinical sign
• Pain usually indicates the presence of infection
• Rapidly expanding cyst may presses on a sensory nerve causes
pain, may referred to any part of the face and is frequently
described as a headache

23. Multiple dentigerous cysts are found, in association with
• basal cell nevus syndrome
• cliedocranial dysplasia
• rare form of amelogenesis imperfecta

24. RADIOLOGIC CLASSIFICATION

25. CLASSIFICATION
• According to Thomas
Central variety:
• Here the crown is enveloped
symmetrically
• Pressure applied to the crown of the
tooth and may be push it away from its
direction of eruption

26. Lateral type:
• In this type the dentigerous cyst is a
radiographic appearance which
results from the dilatation of the
follicle on one aspect of the crown.
• The type us commonly seen when an
impacted molar is partially erupted so
that its superior aspect is exposed

27. Circumferential type
• In this entire tooth appears
to be enveloped by the cyst
• The entire enamel organ
around the neck of the tooth
becomes cystic often
allowing the tooth to erupt
through the cyst

28. • According to Mourshed
 class I dentigerous cyst associated with completely unerupted teeth
Dentigerous cyst associated with unerupted teeth, who fail to erupt
due to lack of space in the dental arch
Dentigerous cyst associated with unerupted teeth, who fail to erupt
due to malpositioning of the tooth germ

29. Dentigerous cyst associated with unerupted supernumerary teeth
Class II dentigerous cyst associated with partial partially erupted
teeth

30. IMAGING FEATURES
 LOCATION
• the epicenter of cyst is found just above the crown of the involved
tooth,
• Important diagnostic point – cyst is attaches at the CEJ
• most commonly mandibular or maxillary 3rd molar or a maxillary
canine.

31. • Cysts related to maxillary 3rd molars
grow into the maxillary antrum and
may become large before they
discovered
• Cyst attached to mandibular molars
my extend a considerable distance
into ramus or lower border mandible

32. PERIPHERY AND SHAPE
• Typically have a well defined cortex with curved outline or circular
outline.
• If infection present, the cortex may be missing

33. INTERNAL STRUCTURE:
• The internal aspect is completely radiolucent except for crown of the
involved tooth

34. EFFECTS ON SURROUNDING STRUCTURES
• May displace and resorb adjacent teeth
• It commonly displaces the associated tooth away from its direction of
eruption
• Thus the maxillary 3rd molar may be found at the floor of the
maxillary antrum

36. • The mandibular 3rd molar may be found at the lower border of the
mandible and in the ascending ramus
• maxillary canine in the sinus as far as the floor of the orbit
• The slowly expanding cyst erodes cortical plates
• Cause resorption of adjacent tooth roots in 55% of cases

37. DIFFERENTIAL DIAGNOSIS
 Hyperplastic follicle
• If the follicular space is more than 5 mm (normal 2-3mm) a
dentigerous cyst is suspected
• The region may be re-examined 4-6 monthly to detect increase inn
size and changes in the surrounding structures

38. Keratocystic odontogenic tumor
• Does not expand the bone to the same degree a dentigerous cyst
• Less likely to resorb teeth
• May attach further apically on root instead of the CEJ

39.  Ameloblastoma and ameloblastomic fibroma
• These are multilocular , most associated with crown of unerupted
tooth
• They grow laterally away from the tooth in comparison with
dentigerous cyst, which envelop the tooth symmetrically
• Common in premolar – molar area

40.  Radicular cyst
• Deep caries or extensive restoration in the primary tooth – radicular
cyst
• At the apex of the primary tooth, surrounds the crown of the
developing permanent tooth positioned apical to it - false diagnosis as
dentigerous cyst (mandibular deciduous molars ,developing
bicuspids)

41. MANAGEMENT
• Surgical removal, may include tooth as well
• Large cyst may treated by marsupialization before removal

42. 3. UNICYSTIC (MURAL) AMELOBLASTOMA

43. UNICYSTIC (MURAL) AMELOBLASTOMA
• The unicystic ameloblastoma that forms in the wall of dentigerous
cyst is the most frequently occurring pericoronal radiolucency
• 5% of all ameloblastoma
• It is 2nd and far less frequent growth pattern seen in the intraosseous
ameloblastoma

44. • The minimum diagnostic criteria - single cystic sac with an
odontogenic epithelium, which is present only in focal areas.
• Unicystic type has a considerably better overall prognosis
• Reduced incidence of recurrence compared with ameloblastoma

45. Clinical features
• 15% to 30% of all ameloblastomas form in the wall of dentigerous
cyst
• Sex predilection – occurring approximately equally in men and
women
• Site- most common in mandibular 3rd molar region
• Age – occurs in younger age group ( average 21.8 yrs)

46. • The unicystic ameloblastoma is asymptomatic and remains
undetected until is seen on the routine radiogragh.
• lesion slowly enlarges , nontender swelling apparent on clinical
examination

47. RADIOGRAGHIC FEATURES
• LOCATION
Most ameloblastomas (80%) develop in the molar ramus region of the
mandible
Most lesions that occur in the maxilla are in the 3rd molar area
• PERIPHERY
Well defined and frequently delineated by a cortical border

48. • INTERNAL STRUCTURE
Totally radiolucent

49. • EFFECT ON SURROUNDING STRUCTURES
 Causes extensive root resorption
 Tooth displacement common
 May cause extreme expansion of the mandibular ramus, and often
the anterior border of the ramus no longer visible in the panoramic
image

51. DIFFERENTIAL DIAGNOSIS
 Dentigerous cyst
• Small unilocular ameloblastomas that are located around the crown
of an unerupted tooth often differentiated from dentigerous cyst.
Residual cyst
• history of extraction the teeth

52. Lateral periodontal cyst
• Found in incisor, canine , premolar area of maxilla
Giant cell granuloma
• Found areas anterior to the molars, younger age group, more
granular and with ill- defined septae

53. MANAGEMENT
• Complete removal with resection
• Intra oral block excision
• Peripheral osteotomy
• Radiation therapy ( inoperable tumors)

54. 4. CALCIFYING ODONTOGENIC CYST
OR TUMOR (CENTRAL)

55. CALCIFYING ODONTOGENIC CYST OR TUMOR
(CENTRAL)
• Approximately 1% of odontogenic tumors
• Synonym- pindborg tumor
• Less aggressive than ameloblastoma
• Majority Intraosseous, rarely extraosseous

56. CLINICAL FEATURES
• Age predilection – 9-92 yrs ( average 40 yrs)
(average age is younger in men and older in women)
• Gender - M=F
• Site predilection – Mandible : maxilla (2:1)
• Commonly occurs as a painless, slowly increasing expansion of jaws
• Palpation of the swelling reveals a hard tumor

57. RADIOGRAPHIC FEATURES
RADIOGRAPHIC APPEARANCE
1. A pericoronal radiolucency
2. A pericoronal radiolucency with radiopaque foci
3. A mixed radiolucent –radiopaque lesion not associated with an
unerupted teeth
4. A “driven snow”appearance
5. Dense radiopacity

58. IMAGING FEATURES
LOCATION
predilection mandibular molar region (68%)>maxillary molar
region> mandibular premolar region
• Mostly associated with unerupted tooth or impacted tooth (52%)
PERIPHERY
• Border may have well defined cyst like cortex
• In some, boundary may be ill defined or irregular

60. INTERNAL STRUCTURE
• Unilocular or multilocular with numerous scattered, radiopaque foci
of varying size and density
• Characteristic diagnostic finding – appearance of the radiopacities
close to the crown of the embedded tooth
• Small, thin, opaque, trabeculae may cross the radiolucency in many
directions

61. EFFECTS ON SURROUNDING
STRUCTURES
• May displace a developing tooth
or prevents its eruption
• Associated expansion of the jaw
with maintenance of a cortical
boundary

62. DIFFERENTIAL DIAGNOSIS
 dentigerous cyst
• cyst is attaches at the CEJ
• most commonly mandibular or maxillary 3rd molar or a maxillary
canine.
Ameloblastoma
• radiolucent with Well defined cortical border
• May multilocular , most associated with crown of unerupted tooth

63. DIFFERENTIAL DIAGNOSIS
 Adenamatoid odontogenic tumor
• More common in anterior maxilla as compared to CEOT
• Common in mandibular premolar – molar region
 ameloblastic fibro odontoma
• Multilocular and radiopacities of enamel and dentin are see inside
the radiolucency

64. MANAGEMENT
• More conservative treatment than ameloblastoma
• Local resection with limited margins

65. 5. ADENAMATOID ODONTOGENIC TUMOR

66. 5. ADENAMATOID ODONTOGENIC TUMOR
• Synonym –adenoameloblastoma , ameloblastic adenamatoid tumor
• uncommon ,benign, and non invasive tumor of odontogenic origin
• 3% of all odontogenic tumors
• Origin is uncertain, but thought to be arises from residual
odontogenic epithelium
• Some investigators considered it as hamartomous malformation

67. Clinical features
• Sex predilection – M:F – 1:2
• Age of occurrence – second decade (Average 17 yrs)
• Types – central and peripheral
central includes follicular and extra follicular
• Tumor is slow growing and manifests as gradually enlarging, painless
swelling or asymmetry, often associated with unerupted tooth

68. RADIOGRAPHIC FEATURES
• LOCATION
• Site - 90% have occurred in anterior portion of the jaws
1⅟2 times more frequent in maxilla
73% occurs association with unerupted teeth or walls of
dentigerous cyst
maxillary canine > lateral incisor > mandibular premolars

70. PERIPHERY
• Well defined corticated or sclerotic border
INTERNAL STRUCTURE
• Internal radiopaque foci develop in two third of cases
• may completely radiolucent, or contain faint radiopaque foci, or some
show dense clusters of well defined radiopacities

71. • Calcifications are small with well defined borders, similar to a cluster
of small pebbles
• Intra oral radiographs may be required to demonstrate the
calcifications within the lesions, which may not be seen in panoramic
radiograph

72. EFFECT ON SURROUNDING STRUCTURES
• As the tumor enlarges, adjacent teeth are displaced
• Root resorption rare
• Inhibit eruption of involved tooth
• Some expansion of jaw occur, the outer cortex is maintained

74. DIFFERENTIAL DIAGNOSIS
• Follicular cyst
The attachment of the radiolucent lesion is more apical than the CEJ
• Calcifying odontogenic cyst
It is difficult to differentiate age group from the extrafollicular typ of
AOT
Occurs in the older age group usually in the premolar-molar area

75.  ameloblastic fibro odontoma
• Found commonly in the posterior mandibular region
• Multilocular and radiopacities of enamel and dentin are see inside the
radiolucency, whereas in AOT the snow flakes are seen at periphery.
 Odontogenic fibroma or myxoma
• Tennis racket appearance

76. MANAGEMENT
• Conservative surgical excision with curettage

77. CONCLUSION
• When the clinician confronted by a pericoronal radiolucency , the
surgical team must be prepared for the anticipated procedure
• Accomplished by the formulation of a list of possible diagnosis
arranged in order of probability

78. Example ……….
A 50 years old woman with a well defined pericoronal
radiolucency associated with impacted lower 3rd molar
DIAGNOSIS????
g

79. Intrafollicular space measuring is 2cm ( normal follicular space
usually decrease in size spaces with age)
Unicystic ameloblastoma – seldom occurs in persons over 30 years of
age
Calcifying odontogenic cyst - occur as a pericoronal radiolucency and
may be unsuspected until small radiopaque foci appear

80. Ameloblastic fibroma, mixed odontogenic tumor occurs most frequently in
mandibular premolar-molar area and seldom in patients over 20 yrs of age
AOT – predilection to anterior region
seen in young persons
Follicular cyst - surrounds the crown
The cyst lining is attached to the neck of the tooth

81. Working diagnosis – dentigerous cyst
unicystic ameloblastoma ( second on the formulated list)

82. REFERENCE
• Differential Diagnosis Of Oral And Maxillofacial Lesions- NORMAN K.
WOOD & PAUL W. GOAZ
• Oral Radiology Principles And Interpretation – STUART C. WHITE &
MICHAEL J. PHAROAH
• Essentials Of Oral & Maxillofacial Radiology – FRENY R KARJODKAR
• Shafer`s Textbook Of Oral Pathology