In the ABCD method used to assess skin lesions for possible skin cancer, what does the A stand for?

• A. Actinic
• B. Asymmetry
• C. Arcus
• D. Assessment

Answer: (B)

Asymmetry is the A in the ABCD method. It means the two halves of a pigmented lesion aren’t mirror images when you draw a line through the center. Benign moles are usually symmetrical, like a smooth oval that would fold in half to match. A lesion that is asymmetric—one side different from the other—raises concern for possible skin cancer because it indicates uneven growth and irregular change in the lesion’s shape.

Other terms aren’t part of this acronym, and they don’t describe the same diagnostic cue. Actinic relates to sun-related damage, arcus is a term used in other contexts, and assessment is a general word rather than a specific diagnostic criterion in the ABCD framework.