Cysts Of The Jaws Flashcards
What is a cyst?
A pathological cavity having fluid, semi-fluid or gaseous contents, and which is not created by accumulation of pus
What are cystic lesions like?
Diverse!
Describe the typical radiographic presentation of a cyst
Shape
- spherical or egg
Margins
- often well defined
- often corticated
Locularity
- often unilocular
- can be multi or pseudolocular
Multiplicity
- single, bilateral, multiple
- multiple often indicates a syndrome
Effect on surrounding anatomy
- displacement of cortical plates, adjacent teeth, maxillary sinus, IAN canal
- root resorption can occur in chronic cysts
Why may a cyst lose its defined corticated margins?
Secondary infection
- typically accompanied by clinical symptoms
How are cysts classified?
Structure - epithelium lined vs not
Origin - odontogenic or non-odontogenic
Pathogenesis - developmental vs inflammatory
Give all odontogenic developmental cysts
Dentigerous cyst
- eruption cyst
Odontogenic keratocyst
Lateral periodontal cyst
Give all odontogenic inflammatory cysts
Radicular cyst
- and residual cyst
Inflammatory collateral cysts
- paradental cyst
- buccal bifurcation cyst
Give non-odontogenic, developmental cyst
Nasopalatine duct cyst
Give non-odontogenic, other, non-epithelial lined cysts
Solitary bone cyst
Aneurysmal bone cyst
What is an odontogenic cyst
Cyst that occurs 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
What are the most common odontogenic cysts and their incidences?
Radicular cyst and residual cyst - 60% of odontogenic cysts
Dentigerous cyst and eruption cyst - 18%
Odontogenic keratocyst - 12% of cysts in maxfax region
What is a radicular cyst? Its incidence?
Inflammatory odontogenic cyst
- always associated with non-vital tooth
- initiated by chronic inflammation at apex of tooth due to pulpal necrosis
60% maxilla
40% mandible
40s and 50s age
Sources of epithelium in cysts?
Hertwigs root sheath
Rests of serres
- remnants of dental lamina
Reduced enamel epithelium
- remnants of enamel organ
Radicular cyst vs periapical granuloma?
Radiolucency >15mm
- 2/3 of cases with be cyst
Periapical granuloma develops into radicular cyst
Presentation of radicular cyst?
Often asymptomatic
- may become infected and become symptomatic
Slow-growing with limited expansion
Radiographic presentation of radicular cyst?
Well-defined, corticated margin, round/oval
- continuous with Lamina dura of non-vital tooth
Long standing lesions may:
- displace surrounding anatomy
- cause external root resorption =
Histology of a radicular cyst
Epithelial lining that is often incomplete
- connective tissue capsule
- inflammation inside the capsule
How does periapical granuloma form a radicular cyst?
Epithelial rests of malassez (hertwigs root sheath remnants) proliferates in the granuloma
What is a residual cyst?
Variant of radicular cyst
- radicular cyst persists after removal of tooth, or after successful RCT
What is a lateral radicular cyst?
Radicular cyst associated with accessory canal
- located at side of tooth and not apex
What is an inflammatory collateral cyst?
Inflammatory odontogenic cyst
- associated with vital tooth
- pouch lined with non-keratinised epithelium
Collective term used for
Paradental cyst - distal aspect of partially erupted mandibular third molar
Buccal bifurcation cyst - buccal aspect of mandibular first molar
What is a Dentigerous cyst?
Developmental odontogenic cyst
- associated with crown of unerupted and usually impacted tooth
- cystic change of dental follicle
Radiographic presentation of Dentigerous cyst?
Corticated margins attached to CEJ of tooth
- larger ones may begin to envelope root of tooth
- may displace involved tooth
- initially symmetrical
- variable displacement of cortical bone
Histology of Dentigerous cyst?
Thin, non-keratinised stratified squamous epithelium
- may resemble radicular cyst if inflamed
When may an enlarged follicle be a Dentigerous cyst?
Follicle space 5mm or more
- crown surface to edge of follicle
Should normally be 2-3mm
Assume cyst if >10mm
What is an eruption cyst?
Variant of Dentigerous cyst
- contained within soft tissue rather than bone
- associated with an erupting tooth
- more commonly incisors and almost exclusive to children
What is an odontogenic keratocyst? Its incidence?
Developmental odontogenic cyst with no specific relationship to teeth
20s-30s
Mandible 3:1 maxilla
Posterior > anterior
Radiographic appearance of odontogenic keratocyst ?
Scalloped margins
25% multilocuar
Often cause displacement of adjacent teeth
Often significant mesial-distal expansion with little bucolic-lingual expansion
Pre-operative diagnostic tests for odontogenic keratocyst
Cyst aspirate
Histology of OKC?
Parakeratosis
Loss of keratin if inflamed
Thin friable lining
What is basal cell naevus syndrome
Multiple odontogenic keratocyst
Multiple basal cell carcinomas
Calcification of intracranial dura mater
Cysts histologically identical to non-syndromes form except these occur younger at around 15
What is a nasopalatine duct cyst? Incidence?
Developmental, non-odontogenic cyst
- arising from epithelial remnants in nasopalatine duct
40s-60s
M>F
What is a nasopalatine duct cyst?
Developmental, non-odontogenic cyst arising from epithelium of nasopalatine duct
40s-60s
M>F
Clinical presentation of nasopaltine cyst?
Often asymptomatic
Pt may report salty discharge
Larger cysts may displace teeth or cause palatal swelling
Always involve mid line but not always symmetrical
Radiographic presentation of nasopalatine cyst?
Corticated radiolucency between / over roots of central incisors
Often unilocular
How monitor incisive fossa vs nasopalatine cyst?
<6mm assume incisive fossa
6-10mm consider monitoring
> 10mm assume cyst
What is a solitary bone cyst? Incidence?
Non-odontogenic cyst without an epithelial lining
20s
M>F
Mandible»_space; maxilla
Clinical presentations of solitary bone cyst?
Usually asymptomatic
- rarely pain or swelling
Radiographic presentation of solitary bone cyst?
Premolar / molar region of mandible
Variable definition and cortication
Scalloped / psuedolocular appearance
May project up between roots of adjacent teeth
What is a stafne cavity?
Not a cyst, but a depression in bone that is filled with salivary or fatty tissue
- always in mandible
- posterior body or angle
- often inferior to IAN
- well defined and corticated
Why take incisional biopsy of cyst?
Obtain sample for histological analysis
- be combined with marsuipialisation sometimes
Options for tx of cyst?
Enucleation
- all of cystic lesion removed
Marsupialisation
- creation of surgical window in wall of cyst so contents can be removed
- encourages cyst to decrease in size
Advantages enucleation?
- Whole lining can be pathologically examined
- primary closure
- little aftercare
- less % recurrence
Contraindications / disadvantages enucleaiton
Risk of mandibular fracture
Would rather Preserve tooth if dentigerous
Old age / ill health
Recurrence higher %
Damage to adjacent structures
Indications for marsupialisation?
If enucleation would damage surrounding tissues such as IAN
When access is difficult
Dentigerous cyst may erupt after
Elderly / immunocompromised
Very large cysts which may cause mandibular fracture
Contraindications / disadvantages to marsupialisation?
Cyst reformation
Complete lining not available for histology
Difficult to clean with lots of aftercare
Long time to fill in
How may a marsupialised cyst be kept open?
Obturator made from thermoplastic retainer
