Non-melanoma skin cancer Flashcards
Which type of UV light penetrates deepest?
UVA (then UVB and UVC)
What is caused by UVA?
It causes tanning and photoaging (A = aging)
What type of UV light makes up the majority that reaches the Earth’s surface?
UVA
What type of UV is emitted by tanning beds?
UVA
What is caused by UVB?
Sunburns (B = burns), delayed tanning, sunspots, some wrinkles, vitamin D synthesis
What type of UV ismost involved in vitamin D synthesis?
UVB
What does UVC light do?
It is the most cancer causing, but also is blocked by ozone
(C = cancer)
What are the two carcinogenic mechanisms of UV radiation?
DNA damage and immunosuppression
What type of UV causes the most direct DNA damage?
UVB
What is the most common effect of direct UV-mediated DNA damage?
Photoproducts such as TT pyrimidine dimers
What is the main cause of indirect DNA damage from UV?
UVA causing reactive oxygen species that cause damage for DNA molecules, cell membranes, and proteins
What gene mutations increase susceptibility to squamous cell carcinomas?
Ras, p53
What gene mutations increase susceptibility for basal cell carcinomas?
PTCH
What gene mutations increase susceptibility to melanoma?
CDKN2A
What are three genetic disorders that predispose people to skin cancer?
Xeroderma pigmentosum, basal cell nevus syndrome, oculocutaneous albinism
What type of UV exposure predisposes to squamous cell carcinoma?
Lifelong, chronic UV radiation
What type of UV exposure predisposes people to basal cell carcinoma?
Intermittent, intense periods of burns
What type of skin cancer has the greatest increase in incidence in transplant patients?
Squamous cell carcinoma (though all skin cancers are increased)
When should a shave biopsy be used?
Used for raised lesions that will provide a specimen with epidermis and superficial dermis
When should a punch biopsy be used?
When you need a full thickness view of the skin that includes subcutaneous fat, dermis, and epidermis
What is the presentation of nodular basal cell carcinoma?
Raised pearly or translucent papule with prominent dilated capillaries, possibly ulceration with larger lesions
What is the presentation of superficial basal cell carcinoma?
Friable thin plaque or scaly red macules, primarily horizontal growth
What is the presentation of morpheaform and infiltrative basal cell carcinomas?
Scar-like flat, atrophic plaques with ill-defined borders
What is the main cause of morbiditiy of basal cell carcinomas?
Soft tissue destruction, metastatic or nodal disease is rare