Odontogenic cysts

Question 1

What is the definition of a cyst?

Answer 1

A pathological cavity with fluid or semi-fluid contents, usually lined by epithelium and not created by pus.

Question 1

What is the typical presentation of cysts?

Answer 1

Slow growing
Asymptomatic
Found as incidental findings sometimes (radiographs)

Question 2

What are the dangers of an untreated cyst?

Answer 2

• Infection
• Displacement of teeth
• Bone resorption (increased risk of pathological fracture)
• Bone infection
• De vitalise teeth
• Can impact vital structures

Question 3

How do you report a radiographic presentation of a cyst?

Answer 3

STOP
S - site, size and shape
T - translucent or opaque
O - outline (well circumscribed etc)
P - any previous imaging

Question 4

What are odontogenic cysts?

Answer 4

Epithelial lining derived from epithelial residues of tooth forming organ (epithelial rests of serres, reduced enamel epithelium, rests of Malassez)

Question 5

What is the most common odontogenic cyst?

Answer 5

Radicular cyst

Question 6

What does a cyst need to grow?

Answer 6

1) source of epithelium
2) stimulus for proliferation of epithelium
3) mechanism of growth and bone resorption

Question 7

What two categories can odontogenic cysts be?

Answer 7

Inflammatory and non inflammatory

Question 8

What are the types of inflammatory odontogenic cysts?

Answer 8

• Radicular
• Residual
• Paradental

Question 9

What are the types of non inflammatory odontogenic cysts?

Answer 9

• Denigerous
• Keratocyst
• Lateral periodontal
• Calcifying odontogenic
• Glandular odontogenic

Question 10

What is the common sites for a radicular cyst?

Answer 10

Jaws - most common in maxilla (anterior maxilla)

Question 11

How do radicular cysts present?

Answer 11

• Asymptomatic usually
• Incidental finding on radiograph

Question 12

What are radicular cysts associated with?

Answer 12

A non vital tooth (usually near apex but can be lateral if a root canal is necrotic)

Question 13

How would you differentiate between a radicular cyst and periapical granuloma?

Answer 13

The larger the lesion the more likely it is to be a cyst

Question 14

What are the radiological features of a radicular cyst?

Answer 14

• round or ovoid radiolucency
  surrounded by a narrow, radiopaque or corticated margin
• extends from lamina dura of involved tooth

Question 15

What are the features of a residual cyst?

Answer 15

• round or ovoid radiolucency
• well demarcated and often corticated margin
• located in edentulous areas of the jaw

Question 16

What is the differential cyst for a residual cyst?

Answer 16

Keratocyst

Question 17

What are the features of a dentigerous cyst?

Answer 17

• odontogenic
• contains/surrounds crown of unerupted tooth
• attaches to the cervical aspect at the CEJ
• develops from expansion of follicle
• eruption cyst

Question 18

Where is it common to have a dentigerous cyst?

Answer 18

Unerupted third molars and canines

Question 19

What are the radiological features of a dentigerous cyst?

Answer 19

Radiolucency envelops the crown of an unerupted tooth (only the crown in the radiolucency)
Unilocular
Corticated margin - continuous with lamina dura
Can become large and displace teeth/resorption on adjacent teeth/distort local anatomy

Question 20

What are the radiological features of an odontogenic keratocyst?

Answer 20

• well defined unilocular radiolucency
• corticated margin
• wide variation
• larger lesions can be multi-locular
• can be associated with unerupted tooth

Question 21

What condition do you need to be aware of when a OKC is diagnosed?

Answer 21

Gorlin Goltz syndrome

Question 22

What are the major features of OKC?

Answer 22

• Multiple BCC’s
• OKC of jaw
• 3 or more palmar pits
  Falx cerebri calcification
  Rib abnormalities
  First degree realtive with basal cell nevus syndrome

Question 23

What is the minor criteria for gorlin goltz syndrome?

Answer 23

Rib abnormalities
Other specific skeletal and radiological abnormalities
Macroencephaly
Cleft lip or palate
Ovarian or cardiac fibroma
Lymph mesenteric cysts
Ocular anomalies

Question 24

What is an eruption cyst?

Answer 24

Painless, blue or translucent cyst that overlies erupted teeth. Common in children.

Question 25

What is a lateral periodontal cyst?

Answer 25

Developmental:
Lateral aspect of tooth/between roots of unerupted teeth
Vital tooth
Asymptomatic
Distinct histopathology
Rare
Adults - peak 5th/6th decade

Question 26

What are the radiological features of a lateral periodontal cyst?

Answer 26

• lateral aspect of tooth between the roots of two teeth
• round/ovoid
• well circumscribed radiolucent area
• corticated, sclerotic margin
• may become tear/pear shaped if teeth are displaced
• usually mid third of root
• mostly <10mm and don’t disrupt lamina dura

Question 27

What is a multi cystic version of a lateral periodontal cyst called?

Answer 27

Botryoid odontogenic cyst

Question 28

What is a glandular odontogenic cyst?

Answer 28

-Epithelium resembles salivary/glandular tissue
-Mandible often cross the midline and symmetrical

Question 29

What are the radiological features of glandular odontogenic cysts?

Answer 29

Well defined, corticated, uni locular or multi, sometimes dentigerous relationship.j