Non-melanomatous skin lesions Flashcards
what are seborrheic keratosis?
benign proliferation of epidermal keratinocytes
stuck on greasy hyperkeratotic surface
common on face and trunk in ageing skin
what occurs with seborrheic keratosis?
epidermal acanthosis
hyperkeratosis
horn cysts
what do seborrheic keratosis look like on histology?
massive thickening of prickle layer with groups of keratinocytes?
circles that look like onions
what are the 3 subtypes of BCC?
nodular
superficial
infiltrative
how do BCCs develop?
basal cells sprout from the epidermis and groups of cells invade into dermis
peripheral palisading
do BCCs spread?
no
slow growing so can divide and grow but don’t metastasise
which type of BCC is most dangerous?
infiltrative
may infiltrate tissues or spread along nerves
poorly defined
physical appearance of BCC?
shiny/pearly
arborizing vessels
what is palisading?
cells line up in a palisade (Picket fence) around the edge of the lesion
seen in nodular BCC
what are superficial BCCs confused with?
eczema as they are almost flat and crusty and are poorly defined
how do superficial BCCs grow?
spread along the base of epidermis and can have gaps so are poorly defined
what does morphoeic look like?
lots of fibroblasts and collagen
looks like a scar
where are BCCs usually derived from?
hair follicle
what is bowens disease?
in situ SCC
usually in older females legs
what does bowens disease look like?
scaly patch/plaque
irregular border
no dermal invasion
yellowish crust sometimes
what happens in bowens?
some cells keratinise prematurely - dysplasia
when does bowens disease become dangerous?
when the dysplasia crosses the basement membrane
who/where is actinic keratoses (AK) usually seen?
on sun exposed (hands, scalp) skin in people with lots of outdoor sun exposure
what are AK?
premalignant dysplasia of epidermis
SCC precursors
what do AK look like?
small crusty lesions
AK histology?
parakeratin - epidermis is turning over too quickly as turning malignant
nuclei retained in keratin layer
squamous dysplasia
name some viral lesions that are precancerous?
erythroplasia of Queryat-penile bowens
associated with HPV
which HPV is associated with dysplasia?
16
common site of SCC?
sun exposed sites
occasional SCC sites?
chronic ulcers
burns sites
chronic lupus
rare site of SCC?
XP
EB
how do SCC behave?
locally invasive
metastases risk but not always
scalp, ear, nose = more likely to spread
can spread via lymphatic, vascular or perineural
SCC histology?
groups of squamous/atypical cells invading the dermis
peri/intra neural spread?
peri = spread around/with the nerves intra = invades the nerve and spreads with it
peri/intra neural spread?
peri = spread around/with the nerves intra = invades the nerve and spreads with it
what do merkel tumours look like?
sheets of dense neuroendocrine cells/tumour
what is the leser trelat sign?
eruptive appearance of many seborrheic kertoses
