SCC and BCC- Geist Flashcards
What are the 2 non-melanoma Skin cancers? And how do they differ from Melanoma?
SCC and BCC.
Unlike Melanoma, these are rarely to infrequently metastatic.
Where do SCCs arise from?
Upper layer of the dermis.
Where do BCC arise from?
Skin containing pilosebaceous units; lowest part of the dermis.
Which one is more metastatic?
SCC (these can metastasize and kill).
On physical examination, SCCs are characteristically what?
Keratotic
Nodular BCCs typically have and lack what, respectively?
- Telangectasias
- Lack Keratin layer
Note: Nodular BCCs tend to break down and erode.
Is Basal Cell carcinoma more common in men or women??
Men
Name the associated results of UV type exposure
UVA- Photoaging, penetrates into dermis
UVB- Skin cancer, sunburn
Note: UVB does not penetrate window glass.
Name the effects of UV on the aging process
- Decreased collagen production
- Decreased glycosaminoglycans
- Increased collagen degradation
- Elastin fragmentation
Discuss how the innate immune system defends against UV light
- Stratum Corneum absorbs UVB to minimize deeper penetration
- Biochromes (melanin) absorb UVA; energy transferred to singlet oxygen and forms ROS.
- ROS deactivated by scavengers
- DNA bases absorb UVB and form pyrimidine dimers
- ROSS react with guanine.
What is the most common skin cancer in darker skin tones?
Squamous Cell Carcinoma
Provide two words to describe an SCC and BCC
SCC
- Nodular
- Keratotic
BCC
- Shiny
- Telangiectasias
Which tumor suppressor gene plays a role in 50% of the skin cancer malignancies?
p53
Describe the stepwise development of SCC over the course of chronic sun exposure.
- Normal skin –> sunlight
- p53 controlling some of the slightly damaged cells
- Additional mutations make it difficult for p53 to manage (dysplastic cells)
- Abnormal cells begin to proliferate and results in full thickness atypia (scc carcinoma in situ) This affects how keratin develops on top of the tissue
- Invasion into the dermis.
What are hypertrophic AKs?
-Hypertrophic Actinic Keratoses are simply thicker AKs.
Note: Up to 50% of Hypertrophic AKs of arms and hands develop into NMSC.
What is Actinic Chelitis?
AKs of the lip.
Note: usually lower lip. This is important to differentiate and rule out SCC of the lip because SCC of the lip is highly invasive.