A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 47-year-old woman comes to her primary care doctor because of a new, pruritic rash. She was gardening in her yard two days ago and now has an eczematous papulovesicular rash on both ankles. You also note a single, 5 mm brown lesion with a slightly raised border on her left thigh. You prescribe a topical corticosteroid for contact dermatitis. Which of the following is the appropriate next step for the thigh lesion?
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A
Further questioningCorrect. Further history (duration, changes, family history) guides whether to monitor, photo-document, or biopsy this incidentally noted lesion.
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B
ReassuranceIncorrect. Reassurance is premature without obtaining a focused history about lesion duration and changes — could miss an evolving melanoma.
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C
Simple shave biopsyIncorrect. Shave biopsy is inappropriate for suspected melanoma because it destroys the deep margin needed for Breslow depth/staging.
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D
Full thickness biopsyIncorrect. Full-thickness (excisional) biopsy may ultimately be needed but should be preceded by history; not every pigmented lesion requires immediate biopsy.
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E
CryotherapyIncorrect. Cryotherapy ablates a lesion without obtaining tissue, eliminating the possibility of histologic diagnosis; a pigmented lesion suspicious for melanoma should never be destroyed without biopsy.
↑ Tap an answer to reveal the reasoning
Answer: A. The thigh lesion in this gardener — a 5 mm brown lesion with a slightly raised border — must be evaluated for melanoma, given the ABCDE criteria (Asymmetry, Border irregularity, Color variation, Diameter >6 mm, Evolution). 'Further questioning' is the appropriate first step because the duration, recent changes, prior appearance, and family history of skin cancer all influence next steps.
If the lesion is new, has been changing, or has irregular features beyond what is seen, biopsy is indicated — but choosing the right biopsy depends on lesion characteristics. For suspected melanoma, a full-thickness excisional biopsy (not shave) is preferred to allow accurate Breslow depth measurement, which guides treatment and prognosis.
Clinical pearl: 'Never shave biopsy a suspected melanoma' — partial sampling destroys the deepest part of the tumor and prevents accurate staging. History-taking first establishes whether biopsy is necessary at all (a stable, longstanding nevus may just need observation/photographic monitoring), and if biopsy is needed, it should be full-thickness excisional with narrow margins.
**Why each option:**
**A.** Correct. Further history (duration, changes, family history) guides whether to monitor, photo-document, or biopsy this incidentally noted lesion.
**B.** Reassurance is premature without obtaining a focused history about lesion duration and changes — could miss an evolving melanoma.
**C.** Shave biopsy is inappropriate for suspected melanoma because it destroys the deep margin needed for Breslow depth/staging.
**D.** Full-thickness (excisional) biopsy may ultimately be needed but should be preceded by history; not every pigmented lesion requires immediate biopsy.