c 1.7: TREATMENT OF INTRA-ORAL BENIGN AND CYSTIC LESIONS OF HARD AND SOFT TISSUES Flashcards
Name the Odontogenic inflammatory cysts x 4
Radicular cyst (dental cyst) - apical - lateral - residual Paradental cyst
Name the non-odontogenic cyst of the jaw
Nasopalatine (duct) cysts/ incisive canal cysts
Name the non-epithelial-lined ‘cysts’ x 3
Stafne bone cyst (Staphne’s idiopathic bone cavity)
Aneurysmal bone cysts
Solitary bone cyst
Soft Tissue cysts which may affect the head and neck x 5
Salivary mucoceles Dermoid cysts Epidermoid cysts Lymphoepithelial cyst Thyroglossal duct cyst Nasolabial cysts
Name the ondontogenic developmental cysts
Dentigerous cyst /Eruption cyst
Odontogenic keratocyst (parakeratotic or orthokeratotic)
Lateral periodontal and botryoid odontogenic cyst
- Gingival cyst
- Glandular odontogenic cyst
Calcifying odontogenic cyst
Name the benign odontogenic tumours
Classified by tissue cell of origin
Ameloblastoma Ameloblastoma, unicystic type Ameloblastoma, extraosseous/ peripheral type Metastasizing (malignant) ameloblastoma Squamous odontogenic tumour Adenomatoid odontogenic tumour Ameloblastic fibroma Primordial odontogenic tumour Odontoma, compound type Odontoma, complex type Dentinogenic ghost cell tumour Odontogenic fibroma Odontogenic myxoma/myxofibroma Cementoblastoma Cemento-ossifying fibroma
Radicular Cysts - histopathology and facts
Most common jaw cysts (~75% all jaw cysts)
- apical (most commonly)
- lateral (formed at lateral canals)
- residual (following extraction of a tooth)
Arise from periapical granuloma from nectrotic remnants of dental pulp
Chronic inflammation (including cytokines and growth factors) stimulates cell rests of malassez - epithelial proliferation, followed by cyst development (due to degeneration of the central cells due to avascular necrosis or necrosis due to toxins) and then growth.
Fluid filled lesions, growth by osmotic pressure, cytokines and prostaglandins released by cells within the capsule causing local bone resorption.
Hydrostatic pressure in the cyst fluid as contents hypertonic compared with serum, so water drawn in along osmotic gradient.
Histologically - non-keratinised squamous epithelial-lined (wholly or in part), supported by chronically inflammed fibrous capsule. Can also get mucous cells (40%) or even cillated respiratory-type cells, and Rushton bodies - hyaline eosinophilic bodies in the lining. Cholesterol clefts may form in the cyst capsule and may produce a shimmering appearance to the fluid.
Can’t tell if periapical granuloma or cyst from radiograph
Rate of expansion estimated at 5mm/year diameter
Maxilla>Mandible
M>F (possibly due to less dental disease in F)
Radicular cysts - signs, symptoms, investigation and management
Possible pain and swelling if infected
Associated with a non-vital tooth
May find expansion, egg-shell crackling, if perforates the cortex - bluish fluctuant submucosal swelling
Investigations - vitality testing tooth and adjacent teeth
Radiographs, possibly CBCT if indicated
Radiographs - well defined unilocular radiolucency with possibly displacement of adjacent structures (e.g. roots/IDC),
Removal of causative tooth/extirpation of necrotic pulp
Small cysts may regress, others require enucleation. Could consider marsupilisation in immunocomprimised/ if large lesion. May consider prophylactic plating if seems high risk of mandibular fracture associated with treatment.
Paradental cysts
Paradental cysts are odontogenic, inflammatory cysts and occur buccally or distobuccally to a tooth affected by pericoronitis. Most commonly affect the mandibular third molar tooth
Radiographically - well defined radiolucency associated with the neck of the tooth and coronal third of the root
Histologically - resemble inflammatory radicular cysts
Dentigerous (and eruption) cysts
- Presentation
- Epidemiology
- Site
- Radiographic features
- Eruption cyst
- Pathogenesis
- Differential?
- Histology
Encloses all or part of the crown of an unerupted tooth
attached at the CEJ
Arises from the follicular tissues
M>F 2:1
Mandible>Maxilla 2:1
MTM>Maxillary canine>MaxillaryTM>mandibular premolar>supernumerary/complex/compound odontomes
Types - central, lateral, circumferential
Radiographically: unilocular, well defined radiolucency associated with the crown of unerupted tooth (which may be displaced). Suspect if follicular space >3mm
Adjacent teeth: displaced, reorbed in ~50%, enveloped by large cysts.
Eruption cysts - extra-alveolar so present as flutuant bluish swellings.
Pathogenesis - stimulus and mechanism of formation unclear
estimated 1% develop cysts
Histopath: Derived from the reduced enamel epithelium (REE)
Occasionally what appears to be ameloblastomous epithelium proliferates into cyst lumen - unicystic ameloblastoma
Lined by thin, non-keratinizing squamous epithelium; often shows mucous cell metaplasia
Odontogenic Keratocyst (Prev OKT)
- Clinical Features
- Radiographic features
- Pathogenesis
Peak incidence 2-3 decades
M>F
Mandible>maxilla (70-80% : 20-30%)
>50% cases mandibular third molar region, ascending ramus, almost all posterior to first premolars
Expansion predominantly in anterior-posterior direction hence few clinical signs - often incidental finding
Multiple cysts associated with Gorlin-Goltz Syndrome
Radiographically - uni/multilocular, well defined, scalloped margin.
(Differential - ameloblastoma/dentigerous cyst if associated with the crown of an unerupted tooth, lateral periodontal cysts.)
May displace adjacent roots
Pathogenesis - Aetiology still speculative. May arise from primordial epithelia (remains of dental lamina) or from the enamel organ before tooth formation, Cell rests of Serres instead of a normal tooth developing - hence sometimes a tooth is missing from the series.
Evidence suggesting PTCH-gene not a significant factor in sporadic OKC
More proilferative than mucosal epithelium. Active epithelial growth more important than osmotic pressure, hence growth pattern and probably affects keratocystic recurrence. Bone resorbing factors produced by the cysts. Cyst has extension of proliferating areas along cancellous spaces.
2 types - Parakeratotic (usually multilocular, more likely to recur) and Orthokeratotic (monolocular)
Recurrence 3-60% - due to friable cell wall, projections into cancellous spaces and satellite cysts
Histology - thin cyst wall, often foldered and lined by regular continuous layer of stratified squamous epithelium 5-10 cells thick. Fibrous capsule thin and tears easily.
Satellite cysts - (often microscopic) known as daughter cysts, involved in recurrance
If secondarily inflamed then may be difficult to differentiate from radicular cyst histologically.
Gorlin-Goltz Syndrome
Autosomal dominant
Also known as Naevoid basal cell carcinoma syndrome
Manifestations:
-facial features - frontal & parietal bossing, broad nasal root
-skin - multiple BCCs unrelated to sun exposure (90% of cases) (earlier onset, slower growth)
-oral - multiple OKCs (90% of cases)
-skeletal - rib anomalies , vertebral deformties, polydactyly (more fingers), cleft lip/palate (~5%)
-CNS - calcified falx cerebri (fold of dura mata), brain tumours
Caused by mutation of tumour suppressor gene on chromosome 9q termed patched (PTCH) gene, probably acting as a tumour supressor
PTCH encodes for a protein which represses transcription of the hedgehog signalling network
Severity of expression varies/ which areas involved.
Mutations in PTCH also reported in sporadic odontogenic keratocysts.
Odontogenic Keratocyst Management
Preferably diagnosis prior to definitive treatment - rule out ameloblastoma and other differentials depending on location - incisional biopsy
Complete enucleation required, or marsupulisation followed by enucleation/resection.
Resection - lowest recurrence but morbidity so not usually advocated. Consider on case by case basis depending on size of OKC
Carnoy’s fluid improves results of enucleation - but no longer available due to being banned by FDA
Some advocate peripheral ostectomy or cryotherapy with liquid nitrogen.
Optimal treatment modality not yet identified - ? medical management in future to manage tumour suppresant gene?
Need follow up with regular radiographic examinations due to risk of recurrence 1.5-4 years in some studies
Nasopalatine (duct) cyst (incisive canal cyst)
- Clinical features
- Radiographic findings
- Pathophysiology
- Management
Arise from the epithelial remnants of the nasopalatine duct.
Present 3-5th decade. Uncommon.
M>F
Asymptomatic/occasional salty discharge/pain if inflamed. Slow-growing.
Most occur in most inferior aspect of the canal or occasionally completely within the soft tissue.
Radiographically - well defined, round, ovoid or heart-shaped radiolucency. Usually in the midline, but may be displaced to one side or another.
If radiolucency at incisive foramen >6mm then consider cystic change.
Histopath - epithelial lined (stratified squamous. pseudostratified cilated columnar (repiratory), often containing mucous cells), supported bu connective tissue campsule. Collections of mucous glands and chronic inflammatory cell infiltrate frequently seen.
Treatment - enucleation - do not recur. On enucleation, may contain the neurovascular bundle.
Staphnes / Static Idiopathic Bone Cyst
Non-epithelial cysts (‘pseudocysts’)
Non-epithelial lined
Incidental radiographic finding of well circumscribed radiolucency with sclerotic margins in area of second or third molar teeth, beneath the inferior dental canal.
Not a true cyst, but an invagination of the medial aspect of the mandible usually containing salivary tissue (or can be lymphoid tissue)
CBCT indicated to confirm diagnosis, but biopsy and exploration not indicated.
Aneurysmal bone cyst
Non-epithelial cysts (‘pseudocysts’)
Benign intra-osseous blood filled cavities; most commonly found in long bones.
Mandible>Maxilla
Unknown aetiology, essentially a vascular malformation
Adolecents/ young adults.
Primary (70%) - no associated previous lesions
Secondary (30%) - history of previous lesions such as fibrous dysplasia or dentigerous cyst
Clinical features - firm, painless, slowly expanding swelling. Sudden expansion suggests bleeding within lesion (often following minor trauma). Pain in 50% presentations
Can cause root resorption.
Radiographically - unilocular or multilocular radiolucencies, with irregular outline. Differential - keratocyst or ameloblastoma
Histologically - multiple blood filled spaces separated by septa with scattered multi-nucleate giant cells.
Treatment - simple curettage - sometimes complicated by severe bleeding. Can recur.
Solitary bone cyst
simple bone cyst, traumatic bone cyst, haemorrhagic bone cyst, latent bone cavity
Non-epithelial lined space that may contain small amount of straw-coloured fluid/no fluid
Most often found in the long bones, rare in the jaws
trauma proposed aetiology with clot formation which is followed by clot degredation, but no subsequent bone formation. The clot is thought to liquify, producing a gas - the oxygen being absorbed, and the nitrogen remaining, which can be found on analysis.
Adolecents
Painless swelling/ incidental radiographic finding. Expansion in around 25%
F>M 3:2
Radiographically - radiolucency extending between roots of involved teeth, well defined, scalloping, commonly in the premolar and molar region of the mandible. Maxillary lesions rare.
? spontaneous resolution after adolescence
Radiological description of jaw lesions
Site/anatomical position
Size
Shape (unilocular, multilocular, psuedolocular, round, oval scalloped, undulating, irregular, regular)
Outline (smooth, punched out, corticated, sclerotic, encapsulated, signs of invasion or blending with normal anatomy)
Relative radiodensity and internal structure (uniform, mixed, radiopaque, ground glass, cottonwool patches, honeycomb appearance, bony septa, identifiable dental tissue)
Effect on adjacent surrounding structures (resorption, displacement, delayed eruption, dirupted development, loss of lamina dura, increased pdl space, alteration of size of pulp chamber, hypercementosis, expansion, ragged destruction, increased density, sclerosis, subperiosteal new none formation, irregular bone remodelling)
Time present (if known)
Location of odontogenic/non-odontogenic lesions
odontogenic - above IDC
non-odontogenic - below IDC
Differential diagnosis radiolucencies of the jaw
?normal or abnormal?
?artefact?
?pathological? (congenital/developmental/acquired)
Lateral Periodontal Cysts
and variants
Rare, developmental cyst. Thought to develop from either cell rests of dental lamina, or remains of the REE on the lateral surface of the root.
Site -lateral surfaces of the roots of vital teeth, lower canine/premolar/upper lateral incisors
less than 1cm diameter
smooth, well defined and corticated, uniformly radiolucent.
If cyst becomes large, may rarely resorb adjacent teeth. Buccal expansion if large.
Differentials - lateral radicular cyst (inflammatory) or odontogenic keratocyst.
Responds well to enucleation.
Occasionally multilocular - described as botryoid as they resemble a bunch of grapes (even more rare than lateral periodontal cysts) - more likely to recur.
Glandular odontogenic cyst - v rare, associated with lateral periodontal cysts
multilocular, pools of mucin and micous cells in epithelium. Strong tendency to recur.
Gingival cysts
Common in neonates, often referred to as epsteins pearls or Bohn’s nodules.
Most disappear spontaneously by 3/12
Arise from remnants of the dental lamia proliferating to form karatinising cysts (cell rests of serres)
In adults - rare - likely represent developmental lateral periodontal cysts in an extra-alveolar location. Can cause bony resorption, resulting in saucer-like defects in the alveolus. Unlikely to recur after enucleation.
Calcifying odontogenic cyst (previously classifed as an odontogenic tumour, reclassified 2017)
Rare, affects any age.
Affects anterior maxilla or mandible.
Unilocular, well defined and corticated radiolucency, calcifying as it matures. Adjacent teeth usually displaced and/or resorbed. 1/3 associated with unerupted tooth.
Intra-osseous or extra-osseous eroding the jaw
Initially may have little calcification, but increasing calcification leads to differentials including odontome or calcifying odontogenic tumour.
Benign, but may recur and can be aggressive.
Enucleation and curettage is treatment of choice.
Nasolabial cysts
Rare
4-5th decade, F>M 4:1
swelling at nasal fold causing distortion to alar base
can cause local resorption of the maxilla
Treatment - excision
lined by squamous or respiratory epithelium
Aetiology unknown
Dermoid Cysts
Sublingual - found in midline beneath tongue and as far down as hyoid
Developmental - believed to arise from epidermal cell rests resulting from the fusion of embryonal processes.
Deeply placed, filled with keratin, giving firmer feel compared to a ranula.
If above mylohyoid - present as a swelling in FOM
If below mylohyoid - present as swelling in the neck
Treatment - excision
Dermoid cysts can arise in the skin of the H&N and can arise from trauma where skin is driven into subepithelial layers. Treatment - excision.
Lymphoepithelial cysts (?prev classified as Branchial cysts)
?Arise from incomplete obliteration of branchial clefts
lateral aspect of the neck, anterior to SCM. Unusually presenting in the oral cavity - generally FOM.
Rarely present with acute infection.
Age of presentation - children, young adults - if over 40 consider base of tongue SCC and cystic metastases
MRI indicated and excision of the branchial cyst tract.
Histologically - lined by stratified squamous epithelium with well-organised lymphoid tissue. Probably arise from salivary epithelium that becomes entrapped by lymphoid tissue.
Lymphoepithelial cysts found in FOM and posterior tongue epithelial inclusion within lymph nodes
