Cysts of the Mouth and Jaws Flashcards
What are cysts?
Pathological cavity, not formed by the accumulation of pus, which may be lined by epithelium and which usually contains fluid or semi-fluid contents
When is the only time cysts will contain pus?
If they become infected
Describe the aetiology and pathogenesis of cysts
- Proliferation of epithelial lining
- Accumulation of fluid within cyst
- Keratin formation
- Resorption of surrounding bone and attempts at repair
- Slow expansive growth
Name 2 types of non epithelial cysts
- Solitary bone cyst
2. Aneurysmal bone cyst
Name 2 types of epithelial cysts
Developmental (odontogenic and non odontogenic)
Inflammatory
Name 3 inflammatory cysts
- Dental / radicular cyst (apical or lateral)
- Residual cyst
- Paradental cyst
Describe the epidemiology of dental cysts
- Most common jaw cyst (70%)
- More common in males
- Wide age range (peak 20-25 year old)
- More common in maxilla than mandible (60:40)
- More common anterior than posterior (60:40)
Describe the clinical features of dental cysts
- Pain, swelling and mobility of the tooth
- Associated with non vital tooth
- Gradual progressive swelling (increase may indicate infection)
- Egg shell cracking may occur
Describe egg shell cracking as a feature of dental cysts
- Rate of expansion exceeds rate of subperiosteal deposition of bone causing progressive thinning of cortical bone
- Cracking is cyst wall breaking on palpation
- Bluish, fluctuant submucosal swelling seen if cortical plate perforated
Describe the radiographic features of dental cysts
- May be large but usually 10-20mm diameter
- Unilocular radiolucency (round or ovoid)
- Well defined margins
- May expand bone
- 90% related to apex, 10% to lateral aspect
- Rarely cause resorption
Describe the pathogenesis of dental cysts
- Contents of necrotic pulp seep out of apical foramina
- Acute inflammatory response evoked
- Persistent stimulus initiates attempts at healing
- Central cavity develops and enlarges by fluid accumulation
Describe the contents of dental cysts
- Cholesterol crystals are common
- High levels of soluble proteins
- Fluid (including pus if infected)
Describe the pathology of a dental cyst
- Irregular lining of stratified squamous epithelium
- Abundant granulation tissue
- Variable inflammatory cell infiltrate
- Thick wall of dense fibrous tissue
- Cholesterol crystals may be present
What is the difference between an apical granuloma and a dental cyst?
An apical granuloma is a mass of fibrous tissue related to apex of non-vital tooth i.e a dental cyst before central cavitation occurs
Describe the radiological findings, pathogenesis and pathology of apical granuloma
Radiology - Similar to dental cyst but smaller (<10mm)
Pathogenesis - Same as dental cyst but less inflammation, epithelial proliferation and no central cavity formation
Pathology - Poorly defined mass of fibrous tissue
What is a residual dental cyst?
A dental cyst which fails to resolve after an extraction
Describe a paradental cyst
- Inflammatory odontogenic cyst which develops in relation to crown or root of a partially erupted tooth (usually third molar)
- No particular clinical significance
- Well defined radiolucency related to neck of the tooth and coronal third of the root
Name 2 common odontogenic cysts
- Dentigerous cyst
2. Odontogenic keratocyst
What is a dentigerous cyst?
- A developmental, epithelial lined cyst which surrounds the crown of an unerupted tooth and is attached to the amelocemental junction
- If associated with a partially erupted tooth, termed an eruption cyst
Describe the epidemiology of dentigerous cysts
- Make up around 15% of all jaw cysts
- Affect male and female equally
- Wide age range (peak 15-25 years)
- Most commonly found on 3, 4, 5 and 8s
- Other cysts may be present in dentigerous relationship
Describe the clinical features of a dentigerous cyst
- Gradual progressive swelling and facial asymmetry
- No pain unless infected
- Infection causes pain and rapid increase in size
- Unerupted (missing) tooth
- Blueish swelling if an eruption cyst
Describe the radiological features of a dentigerous cyst
- May be large
- Unilocular radiolucency with well defined margins
- May expand bone, displace teeth and occasionally resorb teeth
- Always associated with the crown of an unerupted tooth
Describe the pathogenesis of a dentigerous cyst
- Develops within the normal dental follicle of an unerupted tooth
- Fluid accumulates between enamel and reduced enamel epithelium of the follicle
- Lesion expands by luminal fluid accumulation
Describe the pathology of a dentigerous cyst
- Thin lining of non-keratinising stratified squamous epithelium
- Thin fibrous wall
- Very little to no inflammation
What is a keratocyst?
Developmental odontogenic cyst with a characteristic epithelial lining and a high tendency to recur, usually located at the angle of the mandible but can arise anywhere
Describe the epidemiology of keratocysts
- Account for 10% of all jaw cysts
- Affects 2M:1F
- Wide age range (peak 20-40 years)
- Largely found at angle of mandible
- Small number associated with Gorlin Syndrome
Describe the clinical features of a keratocyst
- Gradual progressive swelling and facial asymmetry
- Unerupted tooth
- Large number detected as incidental findings
- May become infected which can lead to pain
Describe the radiological features of keratocysts
- May be small or large
- Well defined radiolucency
- Often multi locular
- May expand bone or displace teeth
- May be associated with unerupted tooth in dentigerous relationship
Describe the pathogenesis of keratocysts
- Arises from odontogenic epithelium, either dental lamina or surface epithelium
- Lesion expands by epithelial proliferation (hydrostatic ofrces)
- Expand in anteroposterior direction and can reach large sizes without causing bony expansion
Describe the pathology of a keratocyst
- Thin layer of highly organised, keratinising, stratified squamous epithelium 5-10 cells thick with a prominent palisaded basal cell layer
- Often in folds
- Changes of secondary inflammation can be seen
- Very little fluid and low levels of soluble protein
Describe the follow up for a patient who has suffered from a keratocyst
- Long term follow up mandatory
- Clinical and radiographical follow up
- Typically recur between year 2 and year 3
- Follow up is annual for first 5 years and 3 yearly therafter
Describe Gorlin Syndrome
- Autosomal dominant trait
- Consists of multiple basal cell carcinomas of skin, vertebral and rib anomalies, temperoparietal bossing with broad nasal root and keratocysts
- Usually present younger than 15 with unusual facial appearance and multiple keratocysts
Describe a nasopalatine cyst
- Developmental cyst of the incisive canal in the palate
- Believed to arise from remnants of nasopalatine ducts
- Can occur within nasopalatine canal or soft tissues of palate at opening of canal
Describe the epidemiology of nasopalatine cysts
- Most common developmental non-odontogenic cyst
- More common in males
- Wide age range (peak 40-50 years)
Describe clinical features of nasopalatine cysts
- Anterior hard palate or incisive papilla
- Swelling with or without discharge
- Discharge tends to occur with infection
- Blanch on pressure (vascular lesion)
- Occasionally painful
Describe the radiological features of a nasopalatine cyst
- Well defined radiolucency
- Unilocular or heart shaped
- Greater than 6mm diameter
- May displace root or expand bone
Describe the pathology of a nasopalatine cyst
- Thin lining of stratified squamous and respiratory type epithelium in varying proportion
- Fibrous tissue wall
- Neurovascular bundle present in wall
- Little inflammation unless infected
Describe a dermoid cyst
- Rare developmental non-odontogenic cyst presenting as “doughy” painless swelling in midline floor of the mouth or lateral canthus of the eye
- Believed to arise from entrapment of embryonic epithelial rests
Describe the epidemiology of dermoid cysts
- 2F:1M
- Wide age range (peak 20-30 years)
- Slow progressive enlargement
- Much less common type of cyst
Describe the pathology of a dermoid cyst
- Thin lining of stratified squamous epithelium with associated hair follicles and sebaceous glands
- Thin fibrous wall
Describe a nasolabial cyst
- Developmental cyst of the soft tissues of the face found within the nasolabial fold
- Believed to arise from remnants of nasolacrimal duct
Describe the epidemiology of nasolabial cysts
- Very rare (<0.5& of all jaw cysts)
- 10% are bilateral
- 4F:1M
- Wide age range (peak in third decade)
Describe the pathology of a nasolabial cyst
- Thin lining of respiratory type epithelium with goblet cells
- May contain cartilage and mucous glands in the wall
Name 5 types of special investigations which can be used for cyst diagnosis
- Vitality testing
- Radiological examination
- USS
- FNA (Fine Needle Aspiration)
- Histopathology
Name 3 methods of managing cysts
- Enucleation
- Marsupialisation
- Resection
Name 4 things the decision on how to manage a cyst rests upon
- Size, location and nature
- Proximity to vital structures
- PMH and fitness for surgery
- Patient co-operation
What is enucleation?
Complete removal of the cyst lining which enables histopathological examination and cavity usually heals with minimal aftercare
Name 2 types of enucleation
- Primary closure
2. Secondary intention
What is secondary intention enucleation?
- Used in cases where cyst cavity is large
- Cyst is packed with BIPP pack to allow cavity to heal slowly and stay clean
- May take several months to heal
What is marsupialisation?
- Partial removal of cyst lining
- Not all cyst lining available for histopathological analysis which may lead to misdiagnosis
- Less invasive
- Requires considerable aftercare and cooperation in keeping cavity clean
Describe the process of marsupialisation
- Removing a window of lesion and suturing cyst lining to surrounding mucoperiosteum
- Cavity is filled with ribbon gauze
- Opening of cyst eliminates osmotic pressure so the cyst will shrink
- Can be used as single treatment or preliminary treatment for enucleation once lesion decreases in size
