Cysts Flashcards
Define a cyst (4)
- A pathologic cavity filled with fluid
- Lined by epithelium
- Surrounded by a connective tissue wall
- Fluid is secreted by cells lining the cavity
Define a cystlike lesion
A pathologic cavity filled with fluid but lacking an epithelium
3 classes of cysts
- Odontogenic cysts
- Nonodontogenic cysts (developmental cysts)
- Cystlike lesions
2 classes of odontogenic cysts
- Inflammatory cysts
- Developmental cysts
Describe the mechanism of cyst enlargement
4 clinical symptoms of cysts
- Swelling
- Lack of pain
- Frequent association with teeth
- Sometimes cyst becomes infected –> painful
Where are cysts located (5)
- Within bone
- Any location in the maxilla or mandible
- Odontogenic cysts most often in tooth-bearing region
- In mandibule –> above mandibular canal
- In maxilla –> may grow into the maxillary sinus
Describe the periphery and shape of cysts (3)
- Well-defined periphery with a thin, radiopaque line
- Sometimes, secondary infection can change this aspect into more sclerotic (thicker) boundary)
- Usually round or oval shape
Describe the internal structure of cysts (3)
- Radiolucent
- Long-standing cysts have calcifications
- Some cysts have septa which produce multiple loculations
5 effects of cysts on surrounding structures
- Tooth displacement
- Tooth resorption
- Bone expansion
- Displacement of the mandibular canal
- Cyst may invaginate into the maxillary sinus
Define a radicular cyst
A cyst that most likely results when rests of epithelial cells in the periodontal ligament are stimulated to proliferate and undergo cystic degeneration by inflammatory products from a nonvital tooth
2 types of inflammatory cysts
- Radicular cysts
- Residual cysts
5 clinical features of radicular cysts
- Most frequent cysts of the jaws
- Arise from nonvital teeth
- Asymptomatic unless secondary infection occurs
- Swelling (large cysts)
- Incidence of radicular cysts is greater between 30 - 60 years
4 radiographic features of radicular cysts
- Located at the apex of a nonvital tooth
- Well-defined cortical border
- Round shape
- Radiolucent
4 effects of radicular cysts on surrounding structures
- Displacement and root resorption of the adjacent teeth
- Cortical expansion
- Invagination into the maxillary sinus
- Displacement of the mandibular canal
4 differential diagnoses of radicular cyst
- Apical granuloma
- Early stage of periapical cemental dysplasia
- Central giant cell granuloma
- Malignant tumor (metastasis)
How to differentiate a radicular cyst from an apical granuloma
- A small radicular cyst may be impossible to differentiate from an apical granuloma
- Well-defined cortical border, size greater than 1 cm are more characteristic of a cyst
How to differentiate early stage of periapical cemental dysplasia from radicular cysts
- Around vital teeth
- Anterior teeth of the mandible
- Black women more prevalent
Define lateral radicular cyst
A radicular cyst originating from an accessory root canal (existence of a lateral root canal)
Differential diagnosis for lateral radicular cyst
Lateral periodontal cyst
Define residual cyst
A cyst that remains after incomplete removal of the original cyst. A radicular cyst or granuloma left after extraction of a tooth.
4 clniical features of residual cysts
- Asymptomatic
- Often discovered on radiographic examination of edentulous area
- Bone expansion
- Pain in the case of secondary infection
6 radiographic features of residual cysts
- Oval or circular shape
- Well-defined border
- Cortical or sclerotic border (if it become secondarily infected)
- Radiolucent
- Cortical expansion
- Tooth displacement or resorption
2 differential diagnoses for residual cysts
- Other solitary cysts (odontogenic keratocyst; slight cortical expansion)
- Stafne bone defect (below the mandibular canal)
5 types of developmental odontogenic cysts
- Dentigerous cyst
- Odontogenic keratocyst
- Lateral periodontal cyst
- Calcifying odontogenic cyst (Gorlin cyst)
- Glandular odontogenic cyst
Define dentigerous cyst
A cyst that forms around an unerupted crown, which begins when fluid accumulates between the epithelium and the crown of an unerupted tooth. Attached at the cementoenamel junction.
Most common cyst of development
Dentigerous cyst
Age group most commonly affected by dentigerous cyst
20 - 30 years
Most frequent locations of dentigerous cysts (4)
- Mandibular third molar
- Upper canine
- Maxillary third molar
- Lower premolar
5 clinical symptoms/findings of dentigerous cysts
- Missing tooth
- Hard swelling
- Facial asymmetry
- No pain
- Sometimes developping around supernumary tooth (mesiodens)
Radiographic location of dentigerous cysts
- Epicenter is found just above the crown
- Cyst attaches at the CEJ
Internal aspect of dentigerous cyst
Radiolucent
Periphery and shape of dentigerous cyst
Well-defined border
Curved outline
4 effects on surrounding structures by dentigerous cysts
- Tooth displacement (apical direction)
- Tooth resorption
- Expansion of the outer cortical boundary
- Displacement of the mandibular canal in an inferior direction
5 differential diagnoses for dentigerous cysts
- Hyperplastic follicle (vs. small dentigerous cyst)
- Odontogenic keratocyst
- Cystic ameloblastoma
- Ameloblastic fibroma
- Adenomatoid odontogenic tumor
How to differentiate between small dentigeorus cyst and hyperplastic follicle
- Size of normal follicular space = 2 - 3 mm
- When follicular space exceeds 5 mm –> dentigerous cyst
3 ways to differentiate odontogenic keratocyst from dentigerous cyst
- OK does not expand bone to the same degree
- OK is less likely to resorb teeth
- OK is not attached to the CEJ
3 ways to differentiate cystic ameloblastoma from dentigerous cyst
- CA presents curved bony septa creating internal compartments
- CA is less homogenous
- CA is not attached to the cementoenamel junction
How to differentiate ameloblastic fibroma from dentigerous cyst
No attachment at the CEJ
How to differentiate between adenomatoid odontogenic tumor and dentigerous cyst
Internal calcifications
Composition of odontogenic keratocyst
Rests of dental lamina
3 tumorlike characteristics of odontogenic keratocyst (keratocystic odontogenic tumor)
- Innate growth potential consistent with a benign tumor
- Growth does not result from osmotic pressure
- Distinctive histologic appearance (epithelial lining is keratinized and thin)
Significance of finding several odontogenic keratocysts
These cysts may constitute part of a basal cell nevus syndrome (Gorlin syndrome)
Frequency of odontogenic keratocysts
3 - 11% of all cystic lesions of the jaws
Age group of odontogenic keratocysts
20 - 40 yrs
Most frequent location of odontogenic keratocysts
Posterior body of the mandible
4 clinical symptoms/findings of odontogenic keratocysts
- No symptoms
- Sometimes mild swelling
- Inside of cyst contains a viscous or cheesy material (characteristic)
- High risk of recorruence (due to small satellite cysts)
Location of epicenter of odontogenic keratocyst
Above the manibular canal
Periphery and shape of odontogenic keratocyst
Curved outline
Evidence of a cortical border
Scalloped outline (contiguous arcs)
Internal structure of odontogenic keratocysts
- Radiolucent
- Occasionally, septa may be present –> multilocular appearance
3 effects of odontogenic keratocysts on surrounding structures
- Teeth displacement
- Flight expansion of the outer cortical boundary –> propensity to grow along the internal aspect of the jaws
- Displacement of the mandibular canal in an inferior direction
5 differential diagnoses for odontogenic keratocysts
- Dentigerous cyst
- Cystic ameloblastoma
- Odontogenic myxoma
- Traumatic cysts
- Central giant-cell granuloma
How to differentiate dentigerous cyst from odontogenic keratocyst
- DC is connected to the CEJ
- DC has a greater propensity to expand the cortical plates
- DC does not present scalloped margin
How to differentiate odontogenic myxoma from odontogenic keratocyst
Trabecular pattern –> fine septa
How to differentiate traumatic cysts from odontogenic keratocysts
Mild cortical plate expansion
How to differentiate central giant cell granuloma from odontogenic keratocyst
Located in the anterior part of the mandible
3 abnormalities associated with basal cell nevus syndrome
- Multiple nevoid basal cell carcinomas of the skin
- Skeletal abnormalities
- Multiple odontogenic keratocysts
Inheritance pattern of Gorlin syndrome
Autosomal dominant inheritance
8 skeletal anomalies of Gorlin syndrome
- Bifid rib
- Vertebral fusion
- Polydactyly
- Temporoparietal bossing
- Mild prognathism
- Flat face
- Multiple OK (high recurrence rate)
- Calcification of the flax cerebri
2 skin lesions assocaited with Gorlin syndrome
- Brown papules
- Basal cell carcinomas (appear later than OK)
Define lateral periodontal cyst
- Cysts which arise from epithelial rests in periodontium lateral to the dental root.
- Developmental odontogenic cyst occuring to the lateral root surface of a vital tooth.
- Usually unicystic but may appear as cluster of small cysts –> boryoid odontogenic cysts
- Do not confuse with lateral radicular cyst (inflammatory origin)
4 clniical features of lateral periodontal cysts
- Asymptomatic
- Less than 1 cm in diameter
- 20 - 60 years
- Male predominance
Location of lateral periodontal cysts
- 50 - 70% observed in mandible
- Mostly in a region extending from the lateral incisor to the second premolar
Periphery and shape of lateral periodontal cysts
- Well-defined lesion
- Round or oval shape
Internal structure of lateral periodontal cyst
- Radiolucent
- Boytroid cyst –> mulitlocular appearance
3 effects on surrounding areas by lateral periodontal cysts
- May efface the LD of the adjacent root
- Tooth displacement
- Bone expansion
4 differential diagnoses fro lateral periodontal cysts
- Small odontogenic keratocyst
- Mental foramen
- Lateral radicular cyst
- Odontogenic tumor (ameloblastoma)
What are calcifying cystic odontogenic tumors (CCOT) associated with 20% of the time
Odontoma
3 clniical features of CCOT
- Age distribution = 20 - 40 yrs
- Slow-growing, painless swelling
- No sex predominance
Location of calcifying odontogenic cysts
Equal distribution between jaws
75% occur anterior to the first molar
Periphery and shape of calcifying odontogenic cysts
- Well-defined lesion
- Curved cystlike shape
- Sometimes ill-defined and irregular
Internal structure of calcifying odontogenic cysts
- Radiolucent
- Calcified material
3 effects on surrounding areas by calcifying odontogenic cysts
- Teeth displacement
- Root resorption
- 20 - 50 % associated with a tooth
3 differential diagnoses for calcifying odontogenic cysts
Lesions having internal calcifications
- Adenomatoid odontogenic tumor
- Ameloblastic fibro-odontoma
- Calcifying epithelial odontogenic tumor
Define glandular odontogenic cyst
- Rare cyst derived from odontogenic epithelium with a spectrum of characteristics including salivary gland features.
- Slight female predominance with a mean age of 46 - 50 yrs
- Aggressive
- High recurrence rate (25 - 30%)
Location of glandular odontogenic cysts
Mostly in anterior madible
Periphery and shape of glandular odontogenic cysts
Curved outline with a cortical boundary
Internal structure of glandular odontogenic cysts
Radiolucent
2 effects of glandular odontogenic cysts on surrounding structures
- Expansion of the cortical plate
- Teeth displacement
Most common of non-odontogenic cysts
Nasopalatine canal cyst (10% of jaw cysts)
Define nasopalatine canal cyst
Cyst resulting from embryonic epithelial rests of nasopalatine duct, which undergo proliferation and cyst degeneration
4 symptoms and findings of nasopalatine canal cysts
- Most often asymptomatic
- Small, well-defined swelling just posterior to the central incisors, salty taste
- Lesion may expand into nasal cavity
- Pressure from the cyst on nasopalatine nerves causes numbness over the palatal mucosa
Location of nasopalatine canal cysts
Nasopalatine canal or foramen, may involve hard palate
Periphery and shape of nasopalatine canal cysts
- Well-defined
- Circular or oval, somtimes heart shaped
Internal structure of nasopalatine canal cysts
Radiolucent
4 effects of nasopalatine canal cysts on surrounding structures
- Divergence of the roots of the central incisors
- Root resorption
- Displacement of the nasal floor in a superior direction
- Expansion of the labial and palatal cortex
2 differential diagnoses of nasopalatine canal cysts
- Large incisive foramen (>6 mm)
- Radicular cyst or granuloma associated with a central incisor
How to differentiate between radicular cyst or granuloma associated with a central incisor versus a nasopalatine canal cyst
Enlargement of the periodontal ligament space and vitality test (should be on non-vital tooth)
4 characteristics of traumatic bone cyst (simple bone cyst)
- Empty cavity within bone
- Lined with connective tissue (not a true cyst)
- Unknown etiology
- May be localized aberration in normal bone remodeling or metabolism
7 clinical features of traumatic bone cysts
- Mostly 10 - 20 yrs
- Male predominance (2:1)
- Multiple may occur with cemento-osseous dysplasia
- Most often asymptomatic
- Occasional pain or tenderness
- Bone expansion or tooth displacement
- Most discovered by chance
Most common location of traumatic bone cyst
Almost all found in mandible (mostly posterior)
Periphery and shape of traumatic bone cysts
Most often well-defined
Curved outline
Occasionally scalloped border
Internal structure of traumatic bone cysts
Totally radiolucent
May appear multilocular (prnounced scalloping –> appearance of septa)
2 effects of traumatic bone cysts on surrounding structures
Often lesion involves all the bone around the roots of teeth but leaves the lamina dura intact
Bone expansion
2 differential diagnoses for traumatic bone cysts
- Odontogenic keratocyst
- Malignant lesion
3 ways to differentiate odontogenic keratocyst from traumatic bone cyst
- OK causes resorption and tooth movement
- MRI shows empty bone cavity for traumatic bone cyst versus cavity filled with fluid in OK
- OK occurs in older age group
2 ways to differentiate malignant lesion from traumatic bone cyst
- No maintenance of lamina dura
- Ill defined and bone destruction
