Dermatopathology Flashcards
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Summarise how different layers of the skin pick up stains (H&E)
Epiderm stain darker - keratinocytes
Then collagen in basement membrane - also pink
Hypodermis - doesn’t really pick up stain
Describe the layers of the epidermis
Made of stratified squamous epithelium
○ Begin life in basal layer - blue - a lot of nuclear material
○ Mature - lose nuclear material - die takes 28-40days
Spinous layer - hook the cells together - stratum spinosum
Granulosum - has granules that are purple
Stratum corneum - water tight barrier - then they are lost at top
Get interspersed melanocytes along the base
Features in the dermis
collagen
hair follicles,
nerves,
sebaceous glands
- everything need for function
What are the major tissue reaction patterns in skin disorders
Spongiotic - intraepidermal intracellular oedema
lichenoid - basal cell damage, interface dermatitis
Psoriasiform - regular epidermal hyperplasia
Vesiculobullous - Blistering within or beneath the epidermis
granulomatous - chronic granulomatous inflammation
vasculopathic - pathological changes in cutaneous blood vessels
Which patterns of skin inflammation happen in the epidermis
Spongiotic
lichenoid
Psoriasiform
vesiculobullous
What patterns of skin inflammation happen in the dermis
Vasculitic
granulomatous
what pattern of skin inflammation happens in the subcutis
panniculitis eg erythema nodosum
What is an example of a spongiotic skin reaction
Eczema
What is the mechanism of eczema -> spongiotic reaction pattern
Lymphyctes in epidermis -> cytokines -> bring fluid in (make look like sponge)
If so much fluid -> vesicles
**Pathological hallmark is oedema **
Example of a lichenoid pattern of inflammation
Lichen planus
Erythema multiforme
TEN
SJS
Pathology of lichen planus
Papules and plaques, purple hue,
Wickham striae - white on top
Keratinocytes become antigenic
Lymphcytes come between dermis and epidermis - attack epidermal keratinocytes
Keratinocytes lost nuclei - apototic keratinocytes
epidermis can slough off -> become ill
Example of a psoriaform reaction
Psoriasis
Pathology of psoriasis
Get thickened epidemis
Epidermis rapidly turning over -> thicker
Hallmark - thick epidermis (psoriasiform hyperplasia)
No time for it to lose its nucleus - see the scale.
Cytokine mileu bring in the neutrophils - see neutrophils in the scale
Appearance and ix for psoriasis
Looks silvery
Effect extensor surface - elbow and knee
Can treat clinically w/o biopsy
Pathology of vesicobullous reaction pattern
Autoimmune
ab attack the epidermis
Summarise bullous pemphigoid
Any age group - common in elderly
Large tense bullae
Itchy
Summarise pathology of bullous pemphigoid
Epidemal basement membrane - destroyed by IgG ab
**Space form between epidermis and dermis - fill with fluid
Lots of eosinophils **
*Direct immunofluresence - *Link to Ig
Get the IgG Ab attacking the basement membrane zone - see linear deposit of IgG where the membrane should be
Pathology of phemphigus
Intercellular juntcion between spinous cells are attacked - cant hold together in epidermis
Foliaceous = superfical
vulgaris = deep
Vulgaris (intraepidermal blistering) - ab attack skin and mucous membrane -attack desmoglein 3 found in the intracellular junctions
Can be lethal - because the skin can slough off
Immunofluresnce around the individual cells - chickenwire pattern
Clinical features of pemiphigus vulgaris
Pathology of sebaceous cyst
Squamous cyst
benign skin tumour
Pathology of seborrhoeic keratosis
In the epidermis
Summarise BCC
Commonest primary skin cancer
Pearly appearance
Rolled edges
Telangiectasia
Virtually never mets
Locally aggressive
Can recur - so need to excise with good margin
Mutation in PTCH gene
Can have Gorhlin’s syndrome - consider if BCC in young
Pathology of BCC
Blue tumours
Cleft artefact
Mitotic activity
Peripheral palisading - all cells stand in line
Pathology of actinic keratosis
Summarise SCC
2nd most common skin cancer
Can metastasise - BV, lymph
More aggressive
Irregular keratinous nodule or a firm erythematous plaque
Freq ulcerate
What is Bowen’s disease
Before SCC get dysplasia
When dysplasia involve full thickness of epidermis, but doesn’t cross basement membrane - bowen’s disease
A lot of mitotic activity- look atypical
Pathology of SCC
Squamous nest break through basement membrane - and into dermis
Pink
Get aggregates of pink cells
○ Keratin pearls
Increased mitotic activity
Perineural invasion - wrap around nerves and travel far
Layer of the skin of benign naevi
Pathology of benign naevi
Small clusters of melanocytes
well spaced
maturation with depth - as you get deeper the melanocytes get smaller and more spindly
A-E EFG for malignant melanoma
Pathology of malignant melanoma
Cellular atypia
Asymmetry
Pagetoid spread - Melanocyte ascend to top of epidermis - should be lower.
a lot of mitosis
disorgansied
Px indicators for melanoma
BRESLOW THICKNESS
○ Histological measurement
○ Main factor that comes into staging melanomas
○ Measured between granular layer to the deepest melanoma cell in the dermis
Ulceration - presence/absence
BRAF V6000E mutations - if patient has this mutation, then you can use it to treat them,
