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Melanoma skin cancer sign: Diameter

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Melanoma skin cancer sign: Diameter

A mole, showing its width compared to a pencil eraser

Melanoma is the most serious type of skin cancer. The most important warning sign of melanoma is a change in the size, shape, or color of a mole or other skin growth, such as a birthmark.

  • A change in diameter (width) is one thing to watch for. Call your doctor if:
    • The width of a mole or skin growth is larger than 1/4 inch (6 mm), or about the size of a pencil eraser.
    • Any mole seems to be growing, even if it is still smaller than 1/4 inch (6 mm).

Current as of: February 27, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Healthwise is a URAC accredited health web site content provider. Privacy Policy. How this information was developed to help you make better health decisions.

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