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Pigmented Skin Lesion OSCE Examination Quiz

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In the ABCDE assessment of a pigmented skin lesion, which feature is often regarded as the single most important warning sign for melanoma?

A Evolution, meaning the lesion is new or has changed in size, shape, colour or symptoms ✓
B Colour variation, meaning there is more than one colour within the lesion
C Diameter, meaning the lesion is larger than expected for a benign mole
D Asymmetry, meaning one half of the lesion does not mirror the other
E Border irregularity, meaning the edge is blurred, notched or uneven

The answer is A: Evolution, meaning the lesion is new or has changed in size, shape, colour or symptoms

Explanation

Why A is correct

See Close Inspection of the Lesion. Option A is correct. Melanoma is a cancer of the melanocytes, the pigment-producing cells of the skin, and the ABCDE criteria are the most familiar tool for deciding whether a pigmented lesion (a mole or patch of coloured skin) looks suspicious. The five features are asymmetry, an irregular border, colour variation, a diameter greater than 6 mm and evolution. Evolution means that the lesion is new or changing in size, shape, colour or symptoms, such as itching or bleeding. It is often regarded as the single most important feature, because a lesion that is changing is far more concerning than one that has been stable for years. The criteria originally had only four features, and a 2004 review of the evidence recommended adding evolution to emphasise how much changing lesions matter in the way melanoma develops. Change cannot be seen in a single look, so you take a focused history alongside the examination, asking whether the lesion is new, whether it has grown or changed colour, and whether it itches or bleeds. A memory aid: the first four features are a photograph of the lesion today, while evolution is the film of how it has behaved over time.

Evolution: a lesion that is new, or changing in size, shape, colour or symptoms.
Why it matters most: a changing lesion is far more concerning than one that has been stable for years.
UK practice: in the weighted 7-point checklist, a change in size is a major feature worth 2 points.

Why the other options are incorrect

B. Colour variation, meaning there is more than one colour within the lesion: Two or more colours within one lesion reflect pigment cells growing at different depths and are highly suggestive of melanoma. Even so, colour variation is a snapshot, and change over time is often singled out as the most important warning sign.
C. Diameter, meaning the lesion is larger than expected for a benign mole: A diameter greater than 6 mm is a recognised warning feature, but small melanomas do occur, particularly when they are found early. Size alone is therefore less decisive than change over time, which can flag a melanoma while it is still small.
D. Asymmetry, meaning one half of the lesion does not mirror the other: Asymmetry, where one half of the lesion does not mirror the other, is a concerning feature because benign moles tend to be symmetrical. It describes the shape at a single moment, whereas a lesion that is new or changing is often regarded as the stronger warning sign.
E. Border irregularity, meaning the edge is blurred, notched or uneven: An irregular, notched or blurred border suggests uncontrolled growth of malignant cells into the surrounding skin, so it is a recognised warning feature. It describes the edge at a single moment and cannot tell you whether the lesion is new or changing.

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More questions from this set. Start the quiz to answer them and see each explanation.

1
A 46-year-old woman with darkly pigmented skin has noticed a pigmented change in her great toenail, which she assumed was a bruise. On close inspection, which finding should most strongly raise concern for melanoma rather than a benign mimic?
2
A 71-year-old man asks about a brown plaque on his upper back that has looked the same for several years. It is sharply defined, with a greasy, warty surface that looks stuck onto the skin. Dermoscopy shows multiple tiny pale cyst-like structures and blackhead-like openings. Which diagnosis best fits these features?

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