Skin Cancer - CG

Question 1

What is the difference between UVA and UVB?

Answer 1

1) UVA: penetrates deeper into skin, (collagen & elastin)
2) UVB: More superficial penetration (sun burns and tans), causes direct damage to DNA of skin cells

Question 2

What is Actinic Keratosis (AK)? What are its risk factors?

Answer 2

AK: precancerous lesion confined to the epidermis (intra-epidermal squamous cell carcinoma).

Risk factors: sun exposure, light complexion, ↑ incidence with age

Question 3

What is the Tx for Actinic Keratosis?

Answer 3

• Cryotherapy
• Surgical removal
• Tretinoin (Retin-A)
• Acid peels w/ glycolic acid
• 5% Fluorouracil topical cream

Question 4

Which skin cancer is more common, Squamous Cell Carcinoma (SCC) or Basal Cell Carcinoma (BCC)? Which one metastasizes? Which one typically follows AK?

Answer 4

1) SCC:
- 20% of all skin cancers
- Substantial risk of metastasis
- AK=precursor

2) BCC:
- 80% of all skin cancers
- Typically do not metastasize
- Locally destructive

Question 5

SCC arises from what?

Answer 5

Keratinocytes

Question 6

UVB damages what DNA gene?

Answer 6

p53 tumor suppressor gene

Question 7

What type of carcinoma is associated with Bowen’s Dz, what lesions are associated with it, and how is it treated?

Answer 7

1) Bowen’s Dz: squamous cell carcinoma in situ
2) Slow growing lesions, slightly elevated, with well-defined borders, grow by lateral extension with induration and ulceration.
3) Tx: Electrodessication & curettage, cryosurgery, 5-FU

Question 8

What are common sites of metastasis for SCC?

Answer 8

if greater than 6 mm deep → ↑ risk of metastasis to regional lymph nodes, liver, lungs, bone

Question 9

What is the Tx for SCC?

Answer 9

• if < 4 mm deep → local excision or electrodessication & curettage (ED&C)
• if > 4 mm deep → Mohs surgery, Lymph Node resection, Radiation therapy

Question 10

Where is BCC commonly found?

Answer 10

• 85% on head and neck
• 25-30% nose alone
• May also occur on sites protected from sun

Question 11

What is the histology of BCC?

Answer 11

• Cells resemble those of the stratum basale (columnar)
• Have a large nucleus
• Appear to form a basal layer by forming an orderly line around the tumor nests in the epidermis/dermis

Question 12

What is the most common histologic pattern of BCC?

Answer 12

Nodular (21%)

Question 13

What is the Tx for BCC?

Answer 13

• If < 2-3 mm deep → ED&C or surgical excision

- If > 2-3 mm deep → Mohs, Cryotherapy, 5-FU, intralesional interferon with phototherapy

Question 14

What type of skin cancer has the highest risk of metastasis and mortality rate??

Answer 14

Melanoma (7,200 death per year)

Question 15

True or False: Skin damage is cumulative?

Answer 15

True

Question 16

What does “ABCDE” stand for, and how can it help us assess for skin cancer?

Answer 16

A. Asymmetry: half of the mole does not match the other half
B. Border: edge of mole is irregular
C. Color: more than one color is present
D. Diameter: larger than 5 mm in diameter
E. Evolving: lesion is evolving/changing

Question 17

What characteristic of skin cancers offers the greatest prognostic value in determining survival rate?

Answer 17

Depth of invasion

Question 18

What is the Golden rule when obtaining specimens of skin growths for diagnostic purposes?

Answer 18

Always obtain full thickness specimen, not a shave biopsy (allows for accurate pathology staging)

Question 19

What are nevi?

Answer 19

benign tumors composed of nevus cells derived from melanocytes.
Different from melanocytes in the following ways:
-Larger
-Lacks dendrites
-More abundant cytoplasm
-contains course granules