Hi - Skin Flashcards
what stain is used in skin histopath
haemotoxin
what colour do the epidermis and dermis stain
epi = purple
dermis = pink
name a key component of the epidermis
keratinoytes
name a key component of the dermis
collagen
how long does it take cells to mature from the base to the surface of the epidermis
28 to 40 days
name the layers of epidermis from outer to inner
desquamated cells
stratum corenum
stratum granulosum
stratum spinosum
BM
what cell is present in the stratum spinosum
desmosomes
in what layer do cells lose their nuclei & what is the benefit
straum corneum
- water tight layer
where are melanocytes in epidermis
stratum spinosum
what is present in the dermis
hair follicles
sweat glands
name the 6 key types of inflammatory skin reactions
spongiotic
lichenoid
psoriasiform
vesiculobullous
graanulomatous
vasculitis
give an example condition of spongiotic reaction
eczema
what is the hallmark feature of spongiotic reaction
intraepidermal intercellular oedema
what is the hallmark feature of lichenoid reaction
band of lymphocytes at epidermal/dermal junction causing keratinocyte death –> interface dermatitis
basal cell damage
what is the hallmark feature of psoriasiform reaction
regular epidermal cells but hyperplasia –> thickened due to increased turnover of keratinocytes
what is the hallmark feature of vesiculobullous reaction
blistering in and beneath epidermis
why do you get oedema in spongiotic
lymphocyte infiltration brings in fluid in perivascular soace
what does spongiotic look like
red, weepy rash with vesicles
give an example condition for lichenoid
lichen planus
describe lichenoid rash
shiny, purple, flat topped, scaly plaques and papules
what line is characteristic of lichenoid
wickham striae - white lines
describe histology of lichenoid
epidermal keratinocytes lose nuclei and apoptose
thickened epidermis
liquefaction degeneration of basal epidermis
melanin beneath epidermis
band of lymphocytes at epidermal/dermal junction causing keratinocyte death
name a subset of lichenoid
erythema multiforme
describe erythema multiforme rash
target lesion
what is erythema multiforme similar to
TEN
Sjorgrens
give an example condition of psoriasiform
psoriasis
describe psoriasiform rash inc location
erythematous plaques, with silver white scales
on extensor surfaces - backs of elbows/knees
describe Ix for psoriasiform rash
clinically usually
biopsy
what causes scales in psoriasiform rash
nuclei still present in keratinocytes in stratum corneum + neutrophils
name 2 types of vesiculobullous
pemphigoid
pemphigus
describe rash of vesiculobullous
large tense bullae, intrinsicly pruritic
pathophysiology of bullous pemphigoid
epidermal BM attacked by IgG AB
eosinophils
fluid filled space between epi/dermis = bullae
where are bullae in pemphigoid
below epidermis
Ix for pemphigoid and finding
direct immunoflurescence
–> IgG attacking BM - linear IgG deposit at BM
name 2 types of pemphigus and their distinction
folliaeceous - superficial
vulgaris - deep
pathophysiology of pemphigus
epidermal cells fall apart as intercellular junction (desmoglien 3) is attacked
rash of pemphigus
blisters / crusts all over skin and mucous membranes
Ix of pempigus and finding
immunoflurescence –> CHICKEN WIRE pattern of intercellular IgG deposits
should pemphigus be Tx?
YES - fatal without tx
what colour is skin tumour in PM
grey
what RF are skin tumours related to & how
sun exposure - superifical solar ilastiosis (reduced collagen / elastic)
name 2 benign skin cancers
seborrhoeic keratosis
sebaceous cyst
3 types of malignant skin cancer
basal cell carcinoma
squamous cell carcinoma
melanoma
clinical features of basal CC
pearly, telangiectasia, rolled edges
prognosis of basal CC inc mets / recurrence
virtually never mets but locally aggressive
can recur
what mutation is associated with basal CC
PTCH mutation for a TS gene
histology of basal CC
blue tumour due to stain
cleft artefact
peripheral palisading - stand in line in nests
histology of SCC
keratin pearls - form pink tumours due to keratin
breaks through BM
increased mitoses
prognosis of SCC inc mets / recurrence
invasive - mets to distal sites by BVs
more aggressive than BCC
what preceeds SCC
acitinic keratosis
describe histopath features of acitinic keratosis
rapid prolfieration
atypia of epidermis
how does acitinic keratosis invasiveness compare to SCC
AK = dysplasia - not broken through BM
SCC = breaks BM
clinical features of acitinic keratosis
rough, scaly
what is bowens disease
full thickness atypia with BM intact
3 types of benign naevi with location
junctional - epidermis
compound - dermis / epidermis
intradermal - dermis
what causes benign naevi and how is it different to cancer
nesting of melanocytes
–> its organised
histology of benign naevi
nice, small nests
well spaced
smaller in depths of dermis
clinical features of melanoma
ABCDE
asymmetry
border - irregular
colour - irregular colouring / pink/red
diameter - >6mm
evolving - changing in size/shape/colour
histology of melanoma
cellular atypia
large melanocytes
asymmetry
pagetoid spread
what is pagetoid spread of melanoma
melanocytes high in epidermis
melanoma stains
melan A stain, S100, HMB45
2 key prognostic indicators of melanoma
breslow thickness
ulceration
other prognostic indicators of melanoma
lymphovascular invasion
perineural invasion
clark level
microsatellites
TILs
regression
mitotic levels
what is breslow thickness
granular layer to deepest keratinocytes
name a common mutation seen in melanoma
BRAF V600E
20-30% of melanoma has this
