Skin Cancer Overview Flashcards
what are the 2 main types of skin cancer?
non-melanomatous (from keratinocytes)
- BCC
- SCC
Melanoma (from melanocytes)
what is BCC?
arises from basal layer
what is SCC?
arises from suprabasal layer
how is skin cancer incidence changing?
increasing worldwide in fair skin populations
SCC increased 334% from 1990-2011
what is responsible for increase in skin cancer?
ageing population (mainly SCC) behavioural change
how common is melanoma?
only 6% of all skin cancers but 75% of skin cancer death
most common type in 16-24 year olds
but sees the same increase in incidence
why are melanomas dangerous?
melanocytes are mobile cells as they move to skin from neural crest so can therefore quickly metastasise (e.g via lymphatics)
what is Breslow thickness?
depth of tumour
how does Breslow thickness effect survival?
<1mm = 95-100% 5 year survival >4mm = 50% metastases = 5%
ABCDE of melanoma diagnoses?
Asymmetry Border Colour Diameter (>6mm) Evolution (changes over weeks/months)
how do you measure a mole?
take 2 measurements and then take same measurements again 6-8 weeks later
what is the ugly duckling sign?
one mole in a collection of many moles looks different
what colour are melanomas?
can be black, red, brown or colourless
what causes a halo (pale area) around a melanoma?
immune system attacking the cancer
are people with many moles at an increased risk of melanoma?
yes
even higher risk if anyone in family has had a melanoma
what is the most common skin cancer?
basal cell (75%)
what are the features of a BCC?
slow growing lump or non-healing ulcer painless locally invasive but doesn't metastasise usually can be cured with skin surgery pearly appearance central ulcer arborizing blood vessels
what are the features of squamous cell carcinoma?
warty, crusted lump or ulcer arises on sun damaged skin faster growth can be painful or bleed more potential to spread
what can a superficial BCC be misdiagnosed as?
eczema
psoriasis
looks like a scaly plaque
how do morphoeic (infiltrative) BCCs present?
like a scar
poorly defined
more difficult to define and remove
what are 4 types of BCC?
superficial
nodular/nodulocystic
morphoeic
pigmented
which is more aggressive BCC or SCC?
SCC
causes most non-melanoma deaths
how does SCC present?
hyperkeratotic lump/ulcer on sun damaged skin usually well differentiated can metastasise but not many grows fast can be painful or bleed
what is a cutenous horn?
crusty growth
type of SCC
can often just be scraped off
how common is developing another non-melanoma cancer after having one?
50% of people get more
what are some high risk sites for SCC?
ear
lip
scalp
where do high risk SCCs often spread?
bone
lymphatics
where else can SCCs arise apart from sun damaged sites?
chronic wounds/ulcers
what are actinic keratoses?
precancerous skin lesions
highly associated with SCC and BCC
if theres many this indicates a field of abnormality
what is bowens disease?
very slow growing erythematous plaque which can be a site for SCCs to develop
what is the main risk factor for skin cancer?
sun exposure
what other factors affect skin cancer skin?
genetics (skin type)
immunosuppression (eg HPV infection)
environmental carcinogens
what genetic factors can increase skin cancer risk?
DNA repair syndromes (xeroderma pigmentosum)
albinism
naevoid BCC (gorlins)
epidermolysis bullosa
what is XP?
xeroderma pigmentosum
genetic disorder where you cant repair sun damaged DNA (NER defect)
how does XP present?
photosensitivity
photodamage
increased skin cancer risk
what does gorlins syndrome increase risk of?
BCC
what is a hallmark of epidermolysis bullosa (RDEB)?
blistering of skin causing mitten deformity of skin
due to deficiency of type 7 collagen
what does epidermolysis bullosa increase the risk of?
SCC
what does immunosuppression increase risk of?
SCC
what is often seen in the hands of transplant patients?
field cancerisation
AKs
SCCs
etc
what environmental carcinogens can increase skin cancer risk?
coal tar ionising radiation trauma chronic ulceration smoking
