The National Cancer Institute provides a webpage dedicated to explaining and displaying images of common moles, dysplastic nevi and risk of melanoma. It is located in the Cancer Topics tab at the top of the page, under the Skin Cancer topic.
The National Cancer Institute first describes and displays images of the common mole as a growth on the skin when pigment cells grow in clusters. It is not uncommon for most adults to have between 10 and 40 common moles. Common moles tend to be smaller than a 1/4 inch, approximately the size of a pencil eraser. Melanoma is a cancerous form of a common mole, and identified by the “ABCDE” rule, as stated by the National Cancer Institute. A stands for asymmetry, B stands for an irregular border, C stands for uneven coloration, D stands for a diameter that is larger than 1/4 inch, and E stands for a mole evolving/changing over the past few weeks or months.