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.
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Asymmetry is one thing to watch for. This means that one half doesn't match the other half. Call your doctor if you notice that:
- One half of a mole doesn't match the other half.
Current as of: May 1, 2026
Author: WebMD Ignite Staff
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