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.
Describe SCC Metastasis facts
- Uncommon to metastasize
- Metastasis is more common when in high risk locations (lips, ears, genitals, perineural)
-Mets first to regional lymph nodes; therefore, dissection of LN can be curative.
Histologically what do we see in SCC
Squamous cells surrounding an island of keratin.The cancerous cells are making the keratin.
Histologically, what do we see in BCC?
Islands of blue cells down into the dermis
Name the gene association with BCC
PTCH
Blocks Smoothened.
Smoothened promotes cell division.
What kind of patients have an increased risk of SCC?
- Organ transplant recipients
- HIV patients (esp. for anal SCC)
What is the definitive way to diagnosis an NMSC?
Skin biopsy
Regarding a punch biopsy, Depth is important for which types?
Melanoma.
Not that important for SCC and BCC.
Painful SCC may indicate what?
The tumor is growing around the nerve.
Name the variants of SCC
V-SPIKE
- Verrucas Carcinoma (slow and well differentiated, invasive)
- SCC from scar
- Periungual (near the nail)
- In situ (confined to top layer)
- Keratoacanthoma (quick growing)
- Erythroplasia of Queyrat (SCC of the genitals)
Describe how an invasive SCC may appear
An ulceration that is not healing; perhaps with a chronic scar.
What is and what causes Erythroplasia of Queyrat?
- SCC of the glans penis
- Caused by HPV 16, 18, 31, 35.
- Uncircumcised men
-Red velvety smooth plaques
Describe the appearance of the Keratoacanthoma?
- This is an SCC variant that is fast growing.
- It is dome shaped with an umbillication.
Note: This may resolve spontaneously.
- Describe the SCC arising from a scar. 2. Discuss the SCC arising in the nail (or around the nail).
- This is a SCC that arises from previously scarred tissue. Ulceration appears in previously healed scar.
- This is Periungual SCC. Associated with HPV.
What is actinic Chelitis?
- This is an AK of the lip. Caused by chronic sun exposure.
- Pre-malignant
- Smoking is a risk factor.
Note: Develops into an SCC that can be highly invasive.
List the clinical subtypes of BCCs
- Superficial
- Nodular
- Micronodular
- Infiltrative/ Morpheaform
Discuss Nodular BCC
- Most common BCC subtype
- Pearly or Shiny Papules
- Rolled borders
- Erosion and ulceration common
- Telangiectasias common
Discuss Pigmented BCC
This is a Nodular BCC subtype
-Can mimic a nevus or Melanoma
Note: More common in darker skin types.
Describe Superficial BCC and the corresponding differentials
-15% of all BCC
Differentials:
- Psoriasis
- Eczema
- Tinea
Discuss Micronodular type BCC
Looks like nodular type. However, histology will reveal smaller islands of tumor cells.
Discuss the Infiltrative and Morpheaform subtypes of BCC
- These have little projections that extend into the dermis. Can be more invasive than what meets the eye.
- Clinically, appear as a small scar. Makes the Dx difficult.
Discuss the topical treatment for BCC,SCC, and AKs.
5-Flurouracil Topical Cream
- Superficial BCC
- AKs
- SCCIS (off label)
Imiquimod
- Superficial BCC
- AKs
- Genital warts
- SCCIS (off label)
Discuss the other treatments for SCC and BCC
- electrodessucation and curettage
- cryo
- laser
- radiation
What is Cryo used for?
- AKs
- BCC, superficial
- CSSC-IS
Describe the surgical interventions and the respective cure rates
Excision
- tumor removed with 4-5mm margins
- specimen sent to lab for histo
- 90% cure rate
MOHS surgery -tumor removed with narrow 1-2mm margins -specimen examined right there; more taken if margins are still positive -BEST cure rate (97-99%) -
What drugs are used in Advanced BCC treatment?
Vismodegib
MOA:
- Hedgehog Inhibitor
- Alters smoothened function
Note:
-Used for metastatic or locally advanced BCC.
Describe the general prevention strategies for the NMSCCs
- Sun protection
- Treat AKs
- Decrease immunosuppression
