Oral Pathology Flashcards
Define cyst
Pathological cavity filled with fluid, semi-fluid or gas freq. lined by epithelium
Never filled with pus
Classification of cysts
Epithelial
- odontogenic
- non-odontogenic
Non-Epithelial
Sub classification of odontogenic cysts
Inflammatory
- radicular; apical, lateral
- residual
Developmental
- odontogenic keratocyst
- dentigerous; follicular, eruption
- lateral periodontal
Sub-classification of non-odontogenic cysts
Fissure (developmental)
- nasopalatine
- nasolabial
- median palatine
Soft tissue
- mucous extravasation
- mucous retention
- dermoid
- lymphoepithelial
- thyroglossal duct
Non-epithelial cysts
Bone
- simple; solitary, haemorrhagic, traumatic
- aneurysmal
3 requirements for cyst pathogenesis
- Epithelial source
- Stimuli for cavitation + epithelial proliferation
- Mechanism(s) for continued growth + bone resorption
Discuss epithelial source of cysts
Inflammatory Cysts
- remnants of Hertwig’s Epithelial Root Sheath
— ensheath’s root dentine
- form epithelial cell rests of Malassez
- throughout PDL, entrapped in periapical granuloma
Dentigerous - reduced enamel epithelium — forms epithelial ‘cover’ for enamel — protects enamel during development + eruption - split b/w REE + enamel -> cyst
Odontogenic keratocyst
- remnants of dental lamina
— initial buds of oral epithelium
- Glands of Serres
Discuss stimulus for cavitation and epithelial proliferation of cysts
Inflammation
- inflammatory cysts usually stim. by inflammation
- site specific: pulp necrosis -> periapical granuloma -> cyst
- PD pocket -> lat. PD inflammatory cyst
- cytokines + growth factors stim. epithelial proliferation
— IL-1+6, TNF, EGF, TGF-beta
Genetic
- possible genetic defect in tumour suppressor gene
- odontogenic keratocyst linked to Gorlin’s syndrome
Discuss mechanisms for continued epithelial growth and bone resorption
Hydrostatic: inflammatory + dentigerous
- protein accumulation in cyst
- wall acts as semi-permeable membrane
- fluid accumulates in cyst lumen creating +ve pressure in cyst
Bone Resorption
- cyst releases cytokines stim. bone resorption
- IL1, TNF, PGE2
Epithelial Growth Factors
- EGF + TGF-beta May cause pronounced epithelial proliferation
- odontogenic keratocyst: pronounced mural growth
— epithelial cells over proliferate
— don’t have lots of expansion
General radiographic presentation of cysts
Well defined round/oval radiolucency
- keratocyst: scalloped margin
Usually, well corticated margin (radiopaque)
- except solitary bone cyst
- infection = loss of definition
Shape
- round due to hydrostatic growth
- keratocyst (+ solitary bone) grow through bone cf expand jaw
Locularity
- true (multiple cavities): keratocyst
- large cysts appear multilocular due to ridges in bony wall
General clinical findings of cysts
Swelling Pain Fluctuance Eggshell cracking Tooth displacement/loosening
Clinical + radiographic findings of radicular cyst
Clinical
- S: non-viral tooth, UIs common
- develop within periapical granuloma (>10mm = cyst)
- regular growth limited; B expansion late
- long standing: displacement + loosening
Radiographic
- unilocular, oval/round
- well corticated
- @ apex non-vital tooth
- continuous w/ lamina dura
Epidemiology + Tx of radicular cyst
Epidemiology: 4-5th decade
Most common cyst; 65%
Tx: RCT, XLA
Discuss residual cysts
Epithelial odontogenic inflammatory cyst
Derived from rests of Malassez
S: edentulous area; retained radicular cyst post-XLA
Radiographic: well defined, oval/round
Histology of radicular/residual cysts
Lumen
- pale pink serious exudate (white if removed)
- macrophages, desquamated epithelial
- inflammatory cells
- cholesterol clefts + foreign body giant cells (if RF; GP, amalgam)
Epithelial
- non-keratinised stratified squamous
- variable thickness, often arcading (hyperplastic rete processes)
- long-standing: thin, attenuated
Capsule: thick wall fibrous + granulation tissue
Inflammatory infiltrate: acute + chronic cells
Clinical + radiographic findings of dentigerous cysts
Clinical
- S: 3s, 8s common
- attached @ CEJ surrounding crown of UE tooth
— confirmed surgically/pathologically (not X-ray)
- envelop crown symmetrically
- late B expansion
Radiographic
- unilocular, well corticated
- crown associated lies centrally in cyst
Epidemiology + Tx of dentigerous cysts
Epidemiology: 3-4th decade
20% of jaw cysts
Tx: uncover tooth, XLA
- no recurrence
Histology of dentigerous cysts
Lumen
- pink serious exudate
- cholesterol clefts
Epithelial
- non-keratinised stratified squamous
- flat basement membrane
- thin (2-5 cells), uniform
- resembles REE
Cyst Wall
- variably thick
- blueish myxoid appearance (like dental follicle)
If becomes inflamed, indistinguishable from inflammatory cyst
Clinical + radiographic findings of odontogenic keratocyst
Clinical: S: Md; angle, ramus
Radiographic - usually multilocular - poss. associated w/ UE tooth - little expansion - grows through medullary bone; late B expansion — root resorption possible
Epidemiology and Tx of odontogenic kerarocyst
Epidemiology: 2-3rd decade
5% jaw cysts
Tx: XLA
- recurrence common due to daughter cysts
Histology of odontogenic keratocyst
Lumen: pink, keratin filled
Epithelial - para/keratinised corrugated surface - flat basement membrane (developmental) - basal cells — reverse nuclear polarity (towards lumen) — darkly staining
Wall: thin, fibrous
Small daughter cysts poss. in wall
- due to epithelial growth grows into marrow spaces
- lots = syndromic
Discuss lateral periodontal cysts
Any cyst in lat. PD area
Epithelial: derived from remnants dental lamina
Clinical: lat. roots vital teeth
Radiographic
- unilocular, well corticated
- round, small (<1cm)
- B expansion if v large
Histology of lat. PD cyst
Epithelial
- non-keratinised stratified squamous
- thin (2-5 cells), not uniform
- thickened areas for swirled plaques
- flat basement membrane
Wall
- thin, fibrous
- scattered glycogen rich clear cells
Clinical + radiographic findings of nasopalatine cyst
Clinical
- S: midline, ant. Mx; vital UIs
- size: >6mm
- asymptomatic
Radiographic
- unilocular, well corticated
- round/oval
- apices of U1s
Histology of nasopalatine cyst
Lumen
- serous exudate
- variable inflammatory infiltrate
Epithelium
- non-keratinised stratified squamous
- ciliated pseudo-stratified respiratory
- both
Wall
- fibrous
- neurovascular bundles
Discuss solitary bone cyst
Non-epithelial non-odontogenic cyst
Usually <20y
Aetiology: unknown, poss. trauma
Clinical
- S: Md body
- asymptomatic
Radiographic
- unilocular, well corticated
- irregular outline; extend b/w roots
Histology of solitary bone cyst
Fibrovascular tissue only
Lumen: usually empty
Epithelial: none
Wall: none/thin fibrous
- occ. giant cells
- haemosiderin pigment; blood vessels were present
Discuss aneurysmal blood cyst
Epidemiology: child, young adult
Aetiology: unknown
Soft tissue lesion; also classified as giant cell lesion
- blood filled cystic spaces
Clinical: S: Md
Radiographic
- multilocular, well corticated
- cortical expansion (ballooning)
- partially cystic, partially solid
Histology of aneurysmal bone cyst
Giant cell lesion
Giant cells in hypervascular, hypercellular background
Localised proliferative lesion of vascular tissue w/ giant cells + granulation tissue
Blood filled cystic spaces
Discuss mucous extravasation and retention cysts
Extravasation - younger - aetiology: trauma - S: L lip - histology — lumen: extravasated mucin — epithelial: none — wall: granulation tissue
Retention - older - S: L lip less common - related to duct obstruction - histology — dilated salivary duct filled w/ mucin — has epithelial lining
Discuss lympho-epithelial cyst
Epidemiology: late childhood, early adulthood
Epithelial: remnants within lymphoid tissue
- stimuli for proliferation unknown
Clinical
- unilateral, fluctuant swelling
- S: lat. neck, ant. sternocleidomastoid
Histology
- attenuated epithelium surrounded by lymphoid stroma
Discuss dermoid cyst
Developmental anomaly
Rare
- F=M
- 15-35; may present earlier/later
Clinical: S: midline FoM, above mylohyoid
Histology
- epithelial: epidermis
- wall: skin appendages (sebaceous glands, hair follicles)
Discuss thyroglossal cyst
Developmental
Occurs when thyroglossal tract left from descent of thyroid doesn’t breakdown
Clinical: S: midline
Histology
- epithelium: attenuated or respiratory
- wall: thyroid follicles (req. for Dx)
Briefly describe tooth development
Neural crest cells (from ectoderm) migrate + clump beneath oral ectoderm
- induce formation 1ry epithelial band
- gives rise to tooth germs
Pre-ameloblast induce odontoblasts
- form dentine which induce ameloblasts
- form enamel of crown
Following fragmentation of Hertwig’s root sheath, dentine formation during root development induce cementoblasts
General features of odontogenic tumours
Derived: odontogenic epithelium (oral ectoderm) +/- mesenchyme
Neoplasm
- abnormal/uncontrolled growth/proliferation
- unrelated to stimuli
- benign or malignant
Hamartoma
- developmental malformation
- normal tissue, incorrect proportion or morphological arrangement
Most odontogenic tumours are benign
- more hard tissue content (mature) = more benign
Classification of odontogenic tumours
Epithelium only
Epithelium + mesenchyme +/- hard tissue
Mesenchyme only
Odontogenic epithelium only tumours
Ameloblastoma: benign, v aggressive Calcifying epithelial: benign Squamous: benign Clear cell: malignant Adenomatoid: enamel, cystic
Odontogenic epithelial + mesenchyme tumours
Ameloblastic fibroma: no hard tissue, both epithelium + mesenchyme neoplastic
Calcifying odontogenic cyst: dentine + enamel like material, cystic
Odontoma: all hard tissues formed
Odontogenic mesenchyme only tumours
Benign cementoblastoma
Odontogenic fibroma: only mesenchyme neoplastic
Myxoma: destructive potential
Epidemiology, freq., origin + Tx ameloblastoma
Benign odontogenic neoplasm
Epidemiology: 20-50y
Freq.: 1% all tumours
Origin: cell rests of enamel organ or dental lamina
Tx
- surgical removal w/ margin (invasive)
- long term follow up due to recurrence
Clinical + radiographic findings of ameloblastomas
Clinical
- S: Md 80% (angle); Mx 20%
- behaviour: slow growing, locally aggressive
- late Dx + incidental finding as mucosa appears normal
- early: asymptomatic
- late
— expansion of cortical plates, egg shell cracking
— extension into soft tissues
— root resorption, painless
— if left: destruction of Md
Radiographic
- multilocular ‘soap bubble appearance’
- well corticated; slow growing, Mx less so
- round/oval, scalloped edge
Histology of ameloblastoma
Solid/cystic/both
Epithelium: resembles ameloblasts
- tall, columnar
- reverse nuclear polarity (prominent basal cells)
Follicular
- epithelial islands
- filled w/ loose stellate reticulum-like cells
- some cystic degeneration (not true cyst)
Plexiform
- interlacing epithelial strands
- less stellate-like cells
Discuss unilocular ameloblastoma
Freq.: 10-15% of ameloblastomas
Radiographic: unilocular
- resembles dentigerous/radicular cyst
Often associated w/ crown UE8
Epidemiology, freq., origin + Tx of calcifying epithelial odontogenic tumours
Benign, solid neoplasm
Epidemiology: 20-60
Freq.: rare, 1% of odontogenic tumours
Origin: odontogenic epithelium, poss. cells of stratum intermedia
Tx: surgical excision w/ margin
Clinical + radiographic features of calcifying epithelial odontogenic tumours
Clinical
- S: Md body 75% (P/M)
- behaviour: slow growing, locally invasive
— usually small; v. large if undetected
- early: asymptomatic
- late: cortical plate expansion, root resorption
Radiographic
- uni/multilocular
- scatter radiopacities; esp. around UE crown
- often associated w/ UE tooth
- ill/well defined, irregular/round
Histology of calcifying epithelial odontogenic tumours
Epithelial
- islands
- pleomorphic, hyperchromatic, prominent nucleoli
- bizarre atypia
- no mitosis, no necrosis
Calcifications
- concentric circles
- laminated
- basophilic
- no pre-dentine layer; abrupt
Epidemiology, freq., origin + Tx ameloblastic fibroma
Benign neoplasm
Epidemiology: <20
Freq.: rare;
Clinical + radiographic findings of ameloblastic fibroma
Clinical
- S: Md body 80%
- behaviour: slow growing
- asymptomatic
- B+L expansion w/ tooth displacement
- 50% associated w/ UE (mistaken for dentigerous)
Radiographic
- resembles ameloblastoma
- small: unilocular, smooth, well corticated
- large: multilocular
Histology of ameloblastic fibroma
Similar to ameloblastoma
Epithelial
- tall, columnar basaolid (ameloblast-like)
- islands + strands
- filled w/ stellate-like cells
Hypercellular mesenchyme in connective tissue (fibroma); usually dominant feature
- looks primitive; too many cells for mature cell
No hard tissues
Epidemiology, freq., origin + Tx of adenomatoid odontogenic tumour
Benign lesion, epithelium + variable hard tissue
Epidemiology: <30
Freq.: v rare
Origin: odontogenic epithelium
Tx: curettage
Clinical + radiographic findings of adenomatoid odontogenic tumour
Clinical
- S: Mx ant., usually associated w/ UE
- behaviour: slow growing, locally expansive
- early: asymptomatic
- late: root resorption, displacement, bony destruction (expansion)
Radiographic
- unilocular, round/oval
- well corticated
- early: resemble dentigerous cyst, extends apical to CEJ
- late: small radiopacities within lesion
Histology of adenomatoid odontogenic tumour
Solid or cystic
Intra-osseous or extra-osseous (gingival swelling-like)
Epithelium
- tall, columnar cells resemble ameloblasts
- from duct-like structures + rosettes (whirls of cells)
Calcifications
- abrupt, basophilic deposits within epithelium
- immature enamel, dentine
- like calcifying epithelial odontogenic tumour
Epidemiology, freq., origin + Tx of calcifying odontogenic cyst
Benign cystic tumour; epithelium + hard tissue
Epidemiology: <40
Freq.: rare
Origin: odontogenic epithelium
Tx: enucleation
Clinical + radiographic findings of calcifying odontogenic cyst
Clinical
- S: Md ant. 80%
- behaviour: slow growing
- early: asymptomatic
- late: local expansion
Radiographic
- unilocular, well corticated
- occ. associated w/ UE/odontome
- radiopacities within lesion
Histology of calcifying odontogenic cyst
Cystic (majority), some solid
75% intra-osseous
Epithelium
- tall, columnar, reverse nuclear polarity
- ameloblast-like
Suprabasal: loose stellate reticulum-like layer Ghost cells (lack nuclei), may calcify
Calcifications: dysplastic dentine
Resembles ameloblasts, diff. by ghost cells + calcifications
Epidemiology, freq., origin, Tx of odontomes
Hamartoma, developmental abnormality (WHO)
Epidemiology: <20
Freq.: most common
Origin: odontogenic epithelium
Tx: XLA
Type of odontome
Compound
- small tooth-like denticles
- tooth shapes of normal radiodensity
Complex
- irregular, haphazard mass
- similar radiopacity to normal
Clinical + radiographic findings of odontomes
Clinical
- S: Mx
- behaviour: slow growing
- asymptomatic, delay eruption/impacted
- local expansion
Radiographic
- similar radiopacity to normal tissue
- associated w/ UE/impacted tooth
- radiolucent line around lesion
Histology of odontome
Resemble developing teeth
- enamel space (white)
- dentine + pre-dentine
- pulp tissue
Compound: organised, separated structures
Complex: irregular, haphazard arrangement
Epidemiology, freq., origin, Tx of odontogenic myxoma
Benign neoplasm, mesenchymal
Epidemiology: young adult, F>M
Freq.: rare
Origin: mesenchyme (fibroblasts)
Tx: excision
Clinical + radiographic findings of odontogenic myxoma
Clinical
- S: Md (angle) > Mx
- behaviour: locally invasive + expansive
- early: asymptomatic
- late: expansion
Radiographic - multi/unilocular — poss. soap-bubble appearance - occ. associated w/ UE - smooth, well defined
Histology of odontogenic myxoma
Hypercellular myxoid ground substance
- contains spindle/stellate cells
- stellate reticulum-like
Epithelium: scattered rests, not neoplastic
Epidemiology, freq., origin + Tx of benign cementoblastoma
Benign neoplasm, mesenchymal
Epidemiology: 10-70; 50% <20
Freq.: rare
Origin: cementoblasts
Tx: excision/enucleation
Clinical + radiographic findings of benign cementoblastoma
Clinical
- S: Md > Mx; P/M
- behaviour: slow growing
- local enlargement + expansive
- root resorption
Radiographic
- well defined dense mass @ apex
- radiolucent margin
- continuous w/ root
Histology of benign cementoblastoma
Cellular cementum - attached to root - resting + reversal lines — mark changes in growth direction — usually indicate fast growing lesion
Fibrous capsule
Histology of alveolar osteitis
Dry socket
Excessive acute inflammatory infiltrate
- lots of neutrophils
- localised to socket wall
Bacterial aggregates
Irregular necrotic bone
Histology of osteomyelitis
Acute - acute inflammatory infiltrate — densely packed neutrophils form pus - necrotic bony islands; acellular — resorbed by osteoclasts
Chronic
- mixed inflammatory infiltrate
- fibrosis
Radiographic findings of osteomyelitis
Ill defined/poorly corticated; loss of cortication
Mottled/moth eaten appearance
Bony sequestra floating
Mixed radio-density
Histology of ORN
Completely acellular bone
- lacunae empty; lack osteocytes
- no osteoblasts on periphery
Bacterial aggregates
- periphery
- bone marrow spaces
Mixed inflammatory infiltrate
Necrosis
Fibrin
Epidemiology and aetiology of fibrous dysplasia
Benign skeletal anomaly
Normal bone replaced by immature disorganised bone + fibrous tissue
Epidemiology
- children, young adults (bones growing)
- F>M
Clinical + radiographic findings of fibrous dysplasia
Clinical: depends on bone(s) affected - S: Mx > Md - behaviour: slow growing, self limiting — stops once bones stop growing - facial asymmetry - tooth displacement + malocclusion
Radiographic
- ground-glass appearance
- ill defined; extends to cortex
- roots + bone appear continuous (not)
- loss of lamina dura
- narrowing of PDL
- early: radiolucent (fibrous)
- late; radiopaque (calcified)
Histology of fibrous dysplasia
Highly cellular fibrous stroma
Bony islands deposited in fibrous tissue
- immature, woven bone
- no osteoblast rim; secreted by fibroblasts
- irregular, curved, haphazard morphology
Epidemiology, freq. and Tx of cemento-ossifying fibromas
Benign neoplasms of jaws + craniofacial skeleton
Epidemiology: 40-59, F>M
Freq.: rare
Tx: excision; recurrence rare
Clinical + radiographic findings of cemento-ossifying fibroma
Clinical - S: Md (P/M) - behaviour: slow growing — no malignant transformation - B+L expansion - painless
Radiographic
- well corticated
- mixed radiodensity
- no fusion b/w roots + bone
Histology of cemento-ossifying
Highly cellular fibrous stroma
Pseudo-capsule: reactive bone
Mineralised tissue deposited within stroma
- reactionary, woven bone
- lamellar bone
- cementum-like tissue
Epidemiology of cemento-osseous dysplasia
Non-neoplastic fibro-osseous condition affecting alveolar bone
Epidemiology
- middle aged
- F
- Afrocaribbean
Types of cemento-osseous dysplasia
PA: PA region, Md, ant.
Focal: single tooth
Florid: multiple sites, multi-Qs
Familial gigantiform cementoma: autosomal dominant, multifocal
Clinical + radiographic findings of cemento-osseous
Clinical
- PA/Focal: asymptomatic, incidental finding
- Florid: minor bony expansion
- FGC: bony expansion, facial deformity
Radiographic
- well defined
- thin radiolucent rim
- mixed radiodensity
- no fusion w/ roots
Mx of cemento-osseous dysplasia
PA/Focal: none, monitor Florid: risk osteomyelitis, regular recall FGC: surgery - risk recurrence - 2ry infection
Histology of cemento-osseous dysplasia
High cellular fibrous stroma Mineralised deposits - woven/lamellar/cementum-like - haphazard, irregular - fuse to from islands - many reversal lines
Epidemiology, freq., aetiology + Mx of Paget’s disease
Epidemiology: >40 Freq.: 1.5-8% popn Aetiology: unknown - genetic - environmental: paramyxovirus
Mx: bisphosphonates
Phases of Paget’s disease
- Osteoclastic: excessive resorption, fibrovascular tissue deposited
- Osteoblastic: new bone formation within fibrous tissue
- Osteosclerotic: bone coalesces -> dense, sclerotic bone
Clinical presentation of Paget’s disease
Jaws rare: Mx > Md
Mx
- widening of alveolar process
- palate flattening
- malocclusion: retroclination UIs, P tipping post.
Md: expansion -> facial deformity
Enlargement Pathological # (weak) Deformity of weight bearing bones Compression of cranial nerves - deafness - visual disturbance - vertigo
Radiographic findings of Paget’s disease
- Radiolucent
- Mixed radiodensity, cotton wool appearance, ill defined
- Very dense, radiopaque
Dental implications of Paget’s disease
Early: highly vascular stroma -> inc. risk post-XLA bleeding
Late: irregular bone + min. vascularity -> inc. risk infection
Hypercementosis: difficult XLA
Histology of Paget’s disease
Mosaic pattern
- haphazard, irregular arrangement of bone
Prominent, basophilic reversal lines
Mature: less vascular
Aetiology of cherubism
Benign, autosomal dominant disorder of childhood
Aetiology: mutation of binding protein gene
Clinical presentation of cherubism
Presents: 2-4y, usually normal @ birth
S: Md > Mx Behaviour: slow growing, self limiting Bilateral, symmetrical expansion Facial deformity - characteristic retracted skin, upwards gaze
Tooth displacement + loosening
Delayed eruption + premature loss
Speech + visual impairments