Oral Pathology Flashcards
What types of specimen are sent for histopathological investigation?
Biopsy - Incisional
Biopsy - Excisional
Resection
What is a fixed specimen preserved in?
10% neutral buffered formalin
How is a fresh specimen preserved?
Frozen
What is the process once a specimen is received at pathology?
- Logged in and assigned unique pathology number
- Macroscopic description and cut-up by pathology (photos & decalcification)
- All biopsy/appropriate blocks taken from resection specimen and placed in cassettes
- Processing - fixation then dehydration of tissue in alcohols
- Embedding - hot paraffin wax to form tissue blocks
- Microtome used to cut sections - 4um thickness
- Sections floated in waterbath, mounted on slide, stained and coverslip placed
- Slides examined
What stains are used routinely?
Haematoxylin and Eosin (H&E)
What other investigations may be used in addition to light microscopy?
Immunofluorescence
In situ hybridization
Electron microscopy
Cytogenetic and molecular genetic analysis
What is hyperplasia?
the abnormal multiplication or increase in the number of normal cells in normal arrangement in a tissue
What is hypertrophy?
the enlargement or overgrowth of an organ or part due to an increase in size of its constituent cells
What is atrophy?
a decrease in cell size by loss of cell substance
What is metaplasia?
reversible change in which one adult cell type is replaced by another adult cell type
What is hyperkeratosis?
thickening of the stratum corneum
What is orthokeratosis?
the formation of an anuclear keratin layer, as in normal keratinised stratified squamous epithelium
What is parakeratosis?
the persistence of nuclei in the cells of a keratin layer
What is dyskeratosis?
premature keratinization of epithelial cells that have not reached the keratinizing surface layer
What is acanthosis?
increased thickness of prickle cell layer
What is acantholysis?
the loss of intercellular adhesion between keratinocytes
What is epithelial dysplasia?
alteration in differentiation, maturation and architecture of adult epithelial cells
What is ulceration?
mucosal/skin defect with complete loss of surface epithelium
What is apoptosis?
programmed cell death
What is necrosis?
cell death by injury or disease
What are developmental white lesion?
Fordyce granules
What are hereditary white lesions?
White sponge naevus
Pachyonychia congenita
Dyskeratosis congenita
What are normal white lesions?
leukodema
What ate traumatic white lesions?
Mechanical/frictional
Chemical
Thermal
What are dermatological white lesions?
Lichen planus
Lupus erythematosus
What are some infective white lesions?
candidosis
syphillitic leukoplakia
oral hairy leukoplakia
What are some idiopathic white lesions?
leukoplakia
proliferative verrucous leukoplakia
what are some neoplastic white lesions?
dysplastic lesions
squamous cell carcinoma
What is the inheritance pattern of white sponge naevus?
autosomal dominant
what is the appearance of white sponge naevus?
ill-defined white patched with ‘shaggy’ surface, often bilateral
where is white sponge naevus found?
any part of oral mucosa, esp buccal
what mutation causes white sponge naevus?
mutations in keratins 4/13
what is the histopathology of white sponge naevus?
hyperparakeratosis and acanthosis of epithelium
basket-weave appearance
what is the treatment of white sponge naevus?
no tx required
what is lichen planus?
common chronic inflammatory disease of skin and mucous membranes
who is most affected by lichen planus?
middle aged and over
females > males
what is the pathogenesis of lichen planus?
T cell-mediated immunological damage to the basal cells of epithelium
what is the most common oral site of lichen planus?
buccal mucosa
what are the different appearances of lichen planus?
reticular
atrophic
plaque-like
papular
erosive
bullous
what is the histopathology of lichenoid inflammation?
hyperorthokeratosis/hyperparakeratosis of the epithelium which may acanthotic or atrophic,
saw-tooth rete ridges
what is an OMPD?
oral potentially malignant disorder
what is an example of an OMPD?
lichen planus
what is the frequency of malignant change in lichen planus?
0.1-10%
what are the clinical features of oral hairy leukoplakia?
white, shaggy appearance on lateral tongue
asymptomatic
what virus causes oral hairy leukoplakia?
EBV and HIV
what is the histopathology of hairy leukoplakia?
thickened, hyperparakeratotic epithelium
band of ‘ballooned’ pale cells in upper prickle cell layer
what is a leukoplakia?
white plaques of questionable risk, once other specific conditions and other OPMDs have been ruled out
how can leukoplakias be described?
homogenous white plaque
nodular / verrucous
what type of cancer can proliferative verrucous leukoplakia degenerate into?
verrucous carcinoma
squamous cell carcinoma
what kinds of red patches are idiopathic?
geographic tongue
erythroplakia
what kinds of red patched are neoplastic?
dysplastic lesions
squamous cell carcinoma
what does median rhomboid glossitis look like?
red patch on midline of posterior aspect of anterior 2/3 of dorsal tongue
what is the histopathology of median rhomboid glossitis?
loss of lingual papillae
parakeratosis and acanthosis of squamous epithelium
candidal hyphae in parakeratin and neutrophils
chronic inflammatory infiltrate in connective tissue
how do you treat median rhomboid glossitis?
antifungal medication
what is the appearance of erythroplakia?
red velvety appearance, smooth or nodular
where is erythroplakia most common?
soft palate, floor of mouth, buccal mucosa
what is erythroleukoplakia?
speckled leukoplakia - leuko and erythroplakia
are erythroplakias prone to malignant transformation?
high likelihood - 50%
what are the exogenous causes of oral pigmentation?
superficial staining (food, drink, tobacco)
black hairy tongue
foreign bodies (amalgam tattoo)
heavy metal poisoning
drugs - NSAIDs, antimalarials, chlorhexidine
what is the histopathology of amalgam tattoo?
pigment dispersed in connective tissue as fine brown/black granules
associated with collagen and elastic fibres and basement membranes
What is a melanotic macule?
well-defined small flat brown/black lesion
what causes a melanotic macule?
increased activity of melanocytes
where are melanotic macules most commonly found?
buccal mucosa, palate and gingiva
Why are melanotic macules frequently excised?
to confirm diagnosis and exclude melanoma
what is the histopathology of melanotic macules?
increased melanin pigment in basal keratinocytes
what is the histopathology of mucosal melanoma?
highly pleomorphic neoplasms, cells appear epithelioid or spindle-shaped
what is the treatment for mucosal melanoma?
surgical resection
adjuvant radiotherapy
what is an ulcer?
localised surface defect with loss of epithelium exposing underlying inflamed connective tissue
what are causes of infective ulceration?
bacterial, fungal, viral (HSV, VZV, CMV, coxsackie)
What are causes of traumatic lesions?
mechanical
chemical
thermal
factitious injury
radiation
what drugs can cause ulceration?
nicorandil (angina)
NSAIDs
name an idiopathic cause of ulceration?
recurrent aphthous stomatitis
what systemic disease can have associated ulcer?
haematological
GI disease
HIV
what dermatological disease has associated ulcers?
lichen planus
discoid lupus erythematous
immunobullous disease
what are neoplastic causes of ulceration?
oral SCC
salivary neoplasms
metastases
what is the histopathology of ulcers?
loss of surface epithelium, inflamed fibrinoid exudate and inflamed granulation tissue
what are the 2 histological classifications of vesicles/bullae?
- intraepithelial
- subepithelial
what are 2 types of intraepithelial vesicles?
non-acantholytic (viral infections eg HSV)
acantholytic (desmosomal breakdown)
how are non-acantholytic vesicles formed?
virus targets and replicates within epithelial cells
leads to cell lysis
groups of infected cells breakdown to form vesicles within epithelium
infected cells infect nearby normal cells and an ulcer forms when the full thickness of the epithelium is involved and destroyed
what is a cause of acantholytic lesions?
pemphigus - autoimmune disease
what causes pemphigus vulgaris?
autoantibodies to desmosomal protein (desmoglein 1 or 3) produced
bullae form in skin and mucous membranes then rupture to leave ulcers
what is the tx for pemphigus
steroids
describe the histopathology of pemphigus
characteristic intraepithelial bullae produced by acantholysis
Tzanck cells found lying free within the bullae fluid
Tombstone-like basal cells remain attached to basement membrane
how is pemphigus vulgaris diagnosed?
direct immunofluorescence (DIF) studies used in conjuction with routine histopathology to confirm diagnosis
what are examples of subepithelial vescicles/bullae?
pemphigoid
erythema multiforme
dermatitis herpetiformis
epidermolysis bullosa acquisita
what is pemphigoid
group of autoimmune diseases:
- bullous pemphigoid
- mucous membrane pemphigoif
- linear IgA disease
- drug induced pemphigoid
how do gingival mucous membrane pemphigoid lesions present?
desquamative gingivitis
what causes mucous membrane pemphigoid lesions?
autoantibodies to basement membrane components (usually BP180, less often integrins, laminin and type VII collagen)
what is the histopathology of mucous membrane pemphigoid?
separation of full thickness epithelium from connective tissue producing subepithelial bullae with a thick roof
infiltration of neutrophils and eosinophils around and within bulla
what is epidermolysis bullosa acquisita?
acquired autoimmune blistering dermatosis with subepithelial bullae
what is epidermolysis bullosa?
formation of skin bullae which heal with scarring
what are the 3 variants of epidermolysis bullosa?
simplex (intraepithelial)
junctional (subepithelial)
dystrophic (subepithelial)
what is oral submucous fibrosis?
chronic, progressive, oral potentially malignant condition
what is oral submucous fibrosis associated with?
betel quid/areca nut
how does oral submucous fibrosis present?
clinically pale coloured mucosa, firm to palpate
increasing submucosal fibrosis leading to very marked trismus
what is the histopathology of oral submucous fibrosis?
submucosal deposition of dense collagenous tissue
decreased vascularity
marked epithelial atrophy
variable rates of dysplasia
what is chronic candidiasis/chronic hyperplastic candidosis?
persistent white patch on oral mucosa that cannot be removed by scraping
what is the most common site for chronic candidiasis/chronic hyperplastic candidosis?
buccal mucosa adjacent to commissure of lips
what is the histopathology of chronic candidiasis/chronic hyperplastic candidosis?
hyperparakeratosis
prominent, irregular acanthosis
numerous neutrophils in parakeratin, forming microabscessed
candidal hyphae in parakeratin
marked inflammation in parakeratin and prickle cell layers
what is epithelial dysplasia?
atypical epithelial alterations limited to the surface squamous epitelium
what are the histological features epithelial dysplasia?
- nuclear and cellular pleomorphism
- alteration in nuclear/cytoplasmic ratio
- nuclear hyperchromatism
- prominent nucleoli
- increased and abnormal mitoses
- loss of polarity of basal cells
- basal cell hyperplasia
- drop-shaped rete pegs
- irregular epithelial stratification or disturbed maturation
- abnormal keratinisation
- loss/reduction of intercellular adhesion
how is epithelial dysplasia graded?
mild - disorganisation, increased proliferation and atypia of basal cells
moderate - more layers of disorganised basaloid cells, atypia, suprabasal mitoses
severe - very abnormal, affects full thickness of epithelium
what is the histopathological difference between dysplasia and OSCC
in dysplasia the atypical cells are confined to the surface
what is the management of epithelial dysplasia?
modify risk factors
high risk sites
antifungal tx
excision
close clinical review
rebiopsy
what are the risk factors of oral cancer?
tobacco
alcohol
betel quid/pan/areca nut
previous oral cancer
exposure to UV light
poor diet
immune suppression
what are the high risk sites for oral cancer?
lateral/ventral tongue
FOM
retromolar trigone
what are low risk sites for oral cancer?
hard palate
dorsum of tongue
what additional detection tests can be used for oral cancer?
toludine blue
autofluorescence
chemiluminescence
vizlite plus
how is SCC diagnosed?
incisional biopsy
what is the histopathology of SCC?
cytologically malignant squamous epithelium, invasion and destruction of local tissues
how is SCC graded?
degree of differentiation:
well-differentatied - tumour cells very obvious
moderately
poorly - may be difficult to identify tumour cells as epithelial