CDT Skin Cancer Screening & Education 3 — Questions and Answers
Question 1: Which of the following best describes an actinic keratosis (AK)?
- A benign keratin cyst with no malignant potential
- A premalignant lesion that may progress to squamous cell carcinoma (Correct answer)
- An in situ basal cell carcinoma
- A variant of melanoma in situ
Correct answer: A premalignant lesion that may progress to squamous cell carcinoma
Actinic keratoses are UV-induced premalignant lesions with potential to progress into invasive squamous cell carcinoma if left untreated.
Question 2: Field cancerization in the context of skin cancer education refers to:
- Multifocal melanoma arising from different primary sites
- A widespread area of UV-damaged skin harboring subclinical genetic mutations (Correct answer)
- Cancerous invasion into regional lymph nodes
- Carcinogenesis caused by radiation therapy fields
Correct answer: A widespread area of UV-damaged skin harboring subclinical genetic mutations
Field cancerization describes large areas of chronically sun-damaged skin with widespread mutagenic changes that predispose to multiple skin cancers.
Question 3: A patient on long-term immunosuppressive therapy after organ transplantation is at highest risk for which skin cancer?
- Basal cell carcinoma
- Merkel cell carcinoma
- Squamous cell carcinoma (Correct answer)
- Melanoma
Correct answer: Squamous cell carcinoma
Immunosuppressed transplant recipients have a dramatically elevated risk—up to 65-fold—for squamous cell carcinoma compared to the general population.
Question 4: The 'ugly duckling' sign in melanoma screening refers to:
- A nevus that is multicolored compared to other nevi
- A lesion that looks noticeably different from a patient's other moles (Correct answer)
- A melanoma arising in an unusual anatomical site
- Any lesion larger than 6 mm in diameter
Correct answer: A lesion that looks noticeably different from a patient's other moles
The 'ugly duckling' concept holds that a melanoma often stands out as morphologically distinct from a patient's other nevi, prompting further evaluation.
Question 5: Breslow thickness in melanoma staging measures:
- Horizontal diameter of the tumor in millimeters
- Vertical depth of tumor invasion from the granular layer in millimeters (Correct answer)
- Number of mitoses per high-power field
- Degree of lymphovascular invasion
Correct answer: Vertical depth of tumor invasion from the granular layer in millimeters
Breslow thickness is the vertical depth of melanoma invasion measured in millimeters from the epidermal granular layer to the deepest tumor cell.
Question 6: Which SPF rating is the minimum recommended by the American Academy of Dermatology for daily photoprotection?
- SPF 15
- SPF 30 (Correct answer)
- SPF 50
- SPF 100
Correct answer: SPF 30
The AAD recommends a broad-spectrum sunscreen of at least SPF 30 for adequate daily photoprotection against both UVA and UVB radiation.
Question 7: Keratoacanthoma is clinically important in the context of SCC because:
- It is a direct precursor that always progresses to invasive SCC
- It can be histologically indistinguishable from well-differentiated SCC (Correct answer)
- It carries a high risk of lymph node metastasis
- It is caused by Merkel cell polyomavirus
Correct answer: It can be histologically indistinguishable from well-differentiated SCC
Keratoacanthoma and well-differentiated SCC can look identical on histology, so most dermatologists treat keratoacanthoma as a variant of SCC.
CDT Skin Cancer Screening & Education 3
Which of the following best describes an actinic keratosis (AK)?