Skin Cancer - Fisher Flashcards
What are some general principles somewhat unique to skin cancer (I know this is vague)?
1) Environmental exposure plays a huge role
2) Potential for early detection
3) noninvasive screening
Describe the histologic appearance of basal cell carcinoma
Nodules of blue epithelium in the epidermis; basophilic, pleomorphic, and hyperchromatic
Describe the histologic appearance of squamous cell carcinoma
Hyperchromatic, pleomorphic nuclei exhibiting disorganized growth. Invasion through the basal layer. Cells are very PINK and keratinizing
What mutation is very common in basal cell carcinoma?
PTCH
What 2 areas confer the greatest risk for metastasis in squamous cell
The lips and ears; good vascular network
Why is the risk of skin cancer increasing in young females?
tanning beds
Risk factors for basal cell carcinoma?
1) UV exposure
2) fair complexion
3) hx of blistering sunburns
4) family hx
5) immunosuppression
3 types of patients at extremely increased risk for squamous cell carcinoma?
HIV, transplant, and rheumatologic patients; both are chronically immunosuppressed
What distinct histologic feature is seen in nodular type basal cell?
a palisade of tumor cells clefting (separating) from the adjacent stroma
(Look at the very right picture)
What pathway does UV radiation mutation that is critical in skin cancers?
Sonic Hedgehog pathway
Where are superificial basal cell carcinomas located histologically?
In the papillary dermis
Describe the gross appearance of a nodular type BCC
“Pimple-like lesion that does not heal and bleeds”
Translucent, pearly paupule with erythema and telangiectasia
Where are BCC commonly located
UPPER LIP most common; Head and neck; central face (sun exposure)
What is the most common subtype of BCC? The 2nd most common?
Nodular most common; superficial 2nd most
Describe the gross appearance of superficial BCC
a flat, very pearly/shiny oval lesion; patient often complains of “chronic area of eczema”
What happens to the appearance of BCC as they progress?
They can start making pigment, become darker
What is important about morpheaform BCC?
It’s the most aggressive type; lacks the features of other BCC so they can normally grow deep prior to clinical detection
Looks like a scar
Describe the gross appearance of a morpheaform BCC
scar-like plaque, lightly colored with ill defined borders
What is Basal cell nevus syndrome (Gorlin Syndrome)?
Mutation of the PTCH1 tumor suppressor gene; BCCs at very early ages –> AD inheritance
Get lots of disfiguring jaw cysts
Metastasis rate of BCC?
Almost non-existent
2 commonly used topical agents in treatment of BCC
Imiquimod and 5-flurouracil
Mechanism of action of Imiquimod
Engages the immune system via TLRs to start an interferon storm and upregulate tumor surveillance
What type of treatment will you NEVER consider with morpheaform BCC
Topical; it has to be excised due to risk of vertical invasion
Targeted therapy for advanced BCC?
Vismodegib
