common skin cancers Flashcards
describe the outline of the skin layers
epidermis
dermis
subcutaneous layer
what does the epidermis layer look like
the epidermis layer looks like: keratinised cells granules cell layer prickle cell layers basal cell layer then the basal lamina in between we have langerhans cells and merkel cells for example
where does proliferation of cells occur
in the basal lamina
describe prickle cell layers
they have intercellular junctions and as they mature they develop keratin granules
what do merkel cells do
proprioceptive functions
where do squamous cells and basal cell carcinomas arise from
the epidermal layer
where do melanomas arise from
melanocytes
describe basal cell carcinomas
commonest malignant tumour
occur on sun exposed sites
metastasis is rare
can be locally aggressive- start in the dermis and move down into SC tissue
what is the risk factor for BCC
UV light- esp in pale people
immunosuppressed
genetic predisposition eg gorlin syndrome or bazex drupe cristol syndrome
describe gorlin syndrome
autosomal dominant
early development occurs of BCC in 20s-30s
1/100000 prevalence
signs and symptoms of gorlin syndrome
palmer pits
odontogenic keratocytes
skeletal abnormality
mental retardation
what can we see clinically in relation to gorlin syndrome
early lesions
ulceration centrally rodent ulcers-with pale edges
describe the histology of BCC
the tumour is composed of islands of basaloid cells with peripheral palisade cells
what do basaxoid cells show up as histologically
dark staining with minimal cytoplasm
what do the low risk types of BCC look like histologically
superficial and nodular
what do the high risk types of BCC look like histologically
infiltrative and micro nodular
describe SCC
more aggressive than BCC
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what are some high risk sites for SCC
lip
ear
perineum
can occur in mucosal sites
what is the metastasis rate in SCC
0.5-5% rate
where does metastasis of SCC occur first
in the lymph nodes
what are some risk factors for SCC
UV exposure high immunosuppressed chronic ulcers radiation bands immunomodulatory drugs eg BRAF inhibitors
what did percivall pott describe
that due to hydrocarbon exposure a lot of chimes sweeps develop SCC
what can SCC look like clinically
scaley
nodular and ulcerated
what can we see microscopically from SCC
arise from keratinocytes
try to replicate what normal cells look like
spinous processes between cells
invade BV and nerves
why do we see actinic keratosis
due to chronic UV exposure
what does acinitic keratosis look like clinically
scaley lesion with erythematous base
rarely progresses to an invasive disease
what does acinitic keratosis look like histologically
abnormal nuclei which are big
where do melanocytes derive from
the neural crest
what is the function of melanocytes
to from melanin which is transferred to epidermal cells to protect the nucleus from radiation
what are benign melanocytic tumours called
naevi
what are malignant melanocytic tumours called
melanomas
describe naevi
local benign collections of melanocytes
where are naevi found
in the superficial dermis and move down the layers
what do naevi look like
uniform and well circumscribed
what are the different types of naevi
superficial
deep
what do deep naevi look like
deep blue colour
describer atypical mole syndrome
irregular shaping of moles
usually with families with an increased melanoma risk
why might people have atypical mole syndrome
due to mutations in the CDKN2A
what does mutations in the CDKN2A gene lead to
atypical mole syndrome
what is a risk factor for atypical mole syndrome
UV exposure
pale skin
family history of melanomas
describe what a naevi looks like
symmetrical even borders uniform colour less than 6mm in diameter lesion hasn't changed over time
what does a melanoma look like
asymmetrical uneven borders different colours greater than 6mm in diameter lesion starts to change over time
what is the most common melanoma in UK
superficial spreading melanoma
what does the early stage of a superficial spreading melanoma look like
a flat macule
what does a late stage of a superficial spreading melanoma look lik
blue/black nodule
what does the late stage of the superficial spreading melanoma look like microscopically
proliferation fo the atypical melanocytes at the dermal epidermal junction which invades the epidermis and then can spread to the BV and nerves
what are some genetic reasons for superficial spreading melanoma
B-RAF proto oncogene mutations
describe nodular melanomas
starts off as a pigmented nodule which can be ulcerated
where are nodular melanomas found
on areas with intermittent sun exposure
what do we see in nodular melanomas microscopically
invasive atypical melanocytes invading the dermis
describe lentigo maligna
found on elderly pts
on sun exposed sites
flat pigmented patch
how is lentigo maligna formed
by disc adhesive single cells and then they go into the dermis
what do we see microscopically in lentigo melanoma
proliferation of abnormal melanocytes along the basal layer
which mutation is commonly seen in letigo maligna
KIT mutations
where are kit mutations commonly seen
lentigo maligna
acral lentiginous melanoma
where can acral lentiginous melanoma be seen
on palms and soles
or sublingual
which group has a predominance to acral lentiginous melanoma
afro carribeans
what does the microscopy seen in acral lentiginous melanoma show
proliferation of abnormal melanocytes along the basal layer
but no marked sun damage
where do mucosal melanomas occur
oral nasal GU GI tract
what do we microscopically see in mucous melanomas
early lengitinous growth along the border between epithelium and CT
which mutations do we see in mucosal melanomas
KIT
GNAQ mutations
what does mucosal melanomas mimic
amalgam pigments
what is prognosis of cancers based on
breslow thickness
where is prognosis works
in the BANS area
if ulcerated
what treatment can we use
surgery removal when small
or if too late
immunotherapy-
what does the breslow thickness look at
the measure between the granular layer to the base of the epidermis
