ABCD guideline

The ABCD guideline refers to a system of criteria for suspecting that a mole (skin marking) is potentially a cancerous melanoma. The initials stand for:
 * Assymetry - the mole is not round
 * Border - the mole's border is not well-defined
 * Color - the mole is dark or varied in color
 * Diameter - the mole is greater than 6mm in size (around the size of a pencil eraser)

If any of the above conditions are present, a biopsy is recommended.