The ABC RuleThe ABC's of skin cancer is a tool to help you identify abnormalities when examining your moles. Each letter represents an abnormal characteristic, including asymmetry, border, color, diameter, and evolution.
- Asymmetry: Normal moles or freckles are completely symmetrical. If you were to draw a line through a normal spot, you would have two symmetrical halves. In cases of skin cancer, spots will not look the same on both sides.
- Border: The borders or edges of an irregular mole are uneven, jagged or blurry.
- Color: Normal moles are uniform in color. Moles are considered to be abnormal when they are more than one color or shade. This can include lightening or darkening of the mole.
- Diameter: If a mole is larger than a pencil eraser (about 1/4 inch, or 6mm), it is considered to be abnormal. This includes moles that do not have any other abnormalities (color, border, asymmetry).
- Evolving: Evolution refers to any changes in the symmetry, borders, colors, and diameter of an existing mole.
In summary, normal moles are typically small, have well-defined borders, are symmetrical, are brown and uniform in color, and are round.