Cysts of Jaws Flashcards
What is a cyst?
- Pathological cavity having fluid, semi-fluid or gaseous contents , not created by accumulation of pus
What are the key features of cysts that can be used to describe a cystic lesion?
Asymptomatic or symptomatic
Slow growing or fast growing
Indolent (lazy) or destructive
Almost all are benign
What radiographic investigations can be utilised in cystic diagnoses?
Initial
- PA
- Occlusal radiograph
- Panoramic
Supplemental
- Cone beam CT
- Facial radio like PA mandible view, occipitomental view
Give some Clinical features of cystic lesions
- Discolouration superficial area
- Loss of vitality and mobility of ass teeth
- May be hard at first then soft to touch (egg shell crackling) *** key to cystic lesion
- Usually slow growing
Describe this picture
- Blueish colour
- Swelling
- Absence of 21
Describe this lesion
- Dark Discolouration on labial surface of gingivae between 31 and 32
- Swelling
When you are describing a cystic lesion from a radiograph what must you include? (7)
- Location
- Shape (often spherical or egg shaped)
- Margins (Often well defined and corticated)
- Locularity (Often unilocular but can be multilocular or pseudolocular)
- Multiplicity (single, bilateral or multiple)
- Effect on surrounding anatomy (displacement of cortical plates, adjacent teeth, max sinus, IANC - variable degree and pattern of growth - root resorption from chronic)
- Inclusion of unerupted teeth
What can multiple cysts indicate?
- A syndrome
if a cyst is secondarily infected what can this change about appearance?
- Lose definition
- Los cortication of margins
- Ass with clinical signs and symptoms
What are the 3 categories that cysts can be classified into?
Structure
- Epithelium lined vs no epithelial lining
Origin
- odontogenic vs non-odontogenic
Pathogenesis
- Developmental vs inflammatory
If a cysts if odontogenic in nature it can be developmental or inflammatory. Give developmental cysts and give Inflammatory cysts
Developmental
- Dentigerous cyst (eruption cyst)
- Odontogenic keratocyte
- Lateral periodontal cyst
Inflammatory
- Radicular cyst (residual cyst)
- Inflammatory collateral cysts either Paradental cyst or Buccal bifurcation cyst
Give non-odontogenic cysts
Developmental
- Nasopalatine duct cyst
Other
- Solitary bone cyst
- Aneurysmal bone cyst
(both other have no epithelial lining)
Give the odontogenic sources of epithelium
Rests of Malassez
- Remnants of Hertwig’s epithelial root sheath
Rests of Serres
- Remnants of dental lamina
Reduced enamel epithelium
- Remnants of enamel organ
Give the epidemiology and incidence of odontogenic cysts
- Occur in tooth bearing areas
- All lined with epithelium
- Most common cause of bony swelling in jaws
- > 90% of all cysts in oral and maxillofacial region
Give the 3 most common odontogenic cysts and their prevalence
- Radicular cyst (residual cyst) approx 60% of odontogenic cysts
- Dentigerous cyst (eruption cyst)
approx 18% - Odontogenic Keratocyst
approx 12% in maxillofacial region
What is a radicular cyst? How do they occur?
- Inflammatory odontogenic cyst
- Always ass with non-vital tooth
- Initiated by chronic inflammation at apex of tooth due to pulp necrosis
What is the incidence of radicular cysts?
Most common 40/50
Equal in male and female
60% maxilla 40% mandible
Can involve any tooth
What is the presentation of radicular cyst?
- Often asymptomatic but when it is infected can cause pain
- Slow growing with lim expansion
Give the stages of non vital tooth becoming a radicular cyst
- Non vital tooth
- Pulpal necrosis
- Periapical periodontitis
- Periapical granuloma
- Radicular cysts
Give the difference of radicular cysts to periapical granulomas
- hard to differentiate radiographically but
- Radicular cysts larger so
if radiolucency >15mm then 2/3rds of cases it is radicular cyst and not PA granuloma
What can cause numbness
- Trauma
- Infection
- Cyst
- Tumour (benign or malignant)
- TN
What is a residual cyst?
- When radicular cyst persists after loss of tooth (or after tooth successfully RCT)
- Avoid misdiagnosis so be thorough with history - recent XLA
What is a lateral radicular cyst?
- Radicular cyst ass with accesory canal
- located at side of tooth instead of apex
What is a nasopalatine duct cyst? Give the incidence. What is it AKA?
- Developmental non odontogenic cyst
- Arises form nasopalatine duct epithelial remnants
- Occurs in anterior maxilla
Incidence
- most comm 40-60ys
- M> F
AKA incisive canal cyst
What is the radiographic description of nasopalatine duct cyst?
PA/ Standard max occlusal
- Corticated radiolucency between/ over roots of central incisors
- often unilocular
- May appear heart shaped due to superimposition of anterior nasal spine
CBCT - needed for better visualisation and surgical planning
How can you tell between incisive fossa or cyst?
Incisive fossa
- May or may not be vis on radiographs
- Midline oval shaped radiolucency
- Typ not visibly corticated
Consider transverse diameter
<6mm = incisive fossa
6-10 = consider monitoring
>10 = suspect cyst
What is the clinical and radiographic presentation of Solitary bone cyst?
Clinical
- Asymptomatic and is an incidental finding
- Rarely pain or swelling
Radiology
- Majority in premolar/molar region of mandible (and non tooth bearing areas)
- Variable definition and cortication
- Scalloped margins giving pseudolocular appearance
- Project up between roots of adjacent teeth
Give the radiographic features of a radicular cyst
- Well defined
- Round/oval radiolucency
- Corticated margin continuous with lamina dura of non vital tooth
- Larger lesions may displace adjacent structures
- Long standing lesions - external root resorption and or contain dystrophic calcification
Give the radiographic features of dentigerous cyst
- Corticated margins attached to cemento-enamel junction of tooth (larger may begin to envelope root of tooth)
- May displace involved tooth
- Tend to be sym initially and when gets larger cysts may expand unilaterally
- Variable displacement of cortical bone (i.e. bony expansion)
