260. Nonmelanoma Skin Cancer

Question 1

Difference between types of UV light (which ones contribute to skin cancer?)

Answer 1

UVA: through clouds/windows, causes tanning and photoAging

UVB: absorbed in epidermis, causes Bunring and delayed tanning

UVC: shielded by ozone, most Carcinogenic

All types contribute to skin cancer

Question 2

Types of nonmelanoma skin cancer and which one is more common.
What is the Fitzpatrick Skin Phototypes?

Answer 2

Basal Cell Carcinoma (75%)
Squamous Cell Carcinoma (25%)
both tumors of keratinocytes

FSP: classify skin based on natural color, ability to tan, ability to burn

Question 3

Two ways of dx keratinocyte carcinomas

Answer 3

1. Shave biopsy: most superficial, minimal bleeding, no sutures, no scars
2. Punch biopsy: for pigmented lesions/deeper lesions (dermal/fat), full thickness specimen, needs sutures/stiches

Question 4

Basal Cell Carcinoma

Biopsy, Gross, likelihood of mets, types

Answer 4

B: rounded nests of basaloid cells (infiltrate downward), peripheral palisading cells, fibromyxoid stroma, cleft formation
G: pearly papule with telangiectasia
Rare to metastasize

Nodular: most common, pearly papule on head/neck
Superficial: pink/translucent patch/placque
Ulcerated
Pigmented: dark pearly papule
Morpheaform: translucent telangectasia rolled border, appears white scar-like plaque

Question 5

Squamous Cell Carcinoma

Gross, Biopsy, Epidemiology, risk of mets, types

Answer 5

large deep pink nodule with central ulceration, firm, crust (horn possible)
B: dermal extension of differentiated keratinocytes, pink keratin pearls
E: more common in people in fair, white skin, more common in immunosuppressed!
Higher risk of mets than BCC

SCC in situ: Bowen’s Disease - circumscribed pink-red patch/thin plaque with scaly/rough surface - like eczema/psoriasis but does not respond to tx

Question 6

Tx of SCC/BCC

Answer 6

Surgery: Cryosurgery, Standard Excision, Mohs micrographic surgery (conserves more tissue and gets whole thing out - good for high risk locations, and aggressive/indistinct/recurrent tumors)

Non-surgical: IMIQUIMOD cream, photodynamic therapy, 5% fluorouracil cream

Prevention: sun avoidance, reduction of immunosuppression

Question 7

Actinic Keratosis

Gross, cell of origin, malignancy, clinical manifestations, tx

Answer 7

G: gritty, scaly, thin red-pink papules on sun-exposed areas
Keratinocyte tumor - premalignant, uncommon to transform to SCC
CM: symptomatic, sun-exposed, erythematous papule with gritty scale (SANDPAPER)
Tx: cryosurgery (may cause post-inflammatory hyperpigmentation), topical imiquimod/5% fluorouracil, photodynamic tx

Question 8

Xeroderma Pigmentosum
Nevoid Basal Cell Carcinoma (Gorlin Syndrome)
Oculocutaneous Albinism

Causes for each, genetics

Answer 8

XP: AR, defect in nucleotide excision repair genes, causes 100s skin cancers at early age

NBCCS: AD, defect in PTCH tumor suppressor (hyperactive Smo/Hh) - predisposed to mulutiple BCCs

OA: Group of disorders - loss of melanin in melanocytes, increases frequency of SCC/melanoma