Moles can appear anywhere on the skin, alone or in groups. They are usually brown in color and can be various sizes and shapes. The brown color is caused by melanocytes which are special cells that produce the pigment melanin.
Each mole has its own growth pattern. At first, moles are flat and tan, pink, brown or black in color, like a freckle. Over time they usually enlarge and some develop hairs. As the years pass, moles usually change slowly, becoming more raised and lighter in color. Some will not change at all. Most moles will slowly disappear, seeming to fade away. Others will become raised so far from the skin that they may develop a small "stalk" and eventually fall off or are rubbed off.
Different Types of Moles
Recent studies have shown that certain types of moles have a higher-than-average risk of becoming cancerous. Some may develop into a form of skin cancer known as malignant melanoma. Sunburns may increase the risk of melanoma. People with many more moles than average (greater than 100) are also more at risk for melanoma and a yearly skin check by your dermatologist is recommended.
Look for danger signs in pigmented lesions of the skin:
A = Asymmetry
When one half of the lesion is unlike the other half.
B = Border
An irregular, scalloped or poorly circumscribed border.
C = Color
When the color of the mole is varied from one area to another–shades of tan, and brown, black and sometimes white, red or blue.
D = Diameter
While melanomas are usually greater than 6mm in diameter (the size of a pencil eraser) when diagnosed, they can be smaller. If you notice a mole that looks different from the others, have noticed changed within a mole, or if it begins to itch or bleed (even if it is small), you should see a dermatologist.