Find an Ugly Duckling 

Doctors have also come up with another simple way to remember the signs of a cancerous mole. The "Ugly Duckling" test is based on scientific research that shows that a person's moles tend to look like each other in the same way that siblings resemble each other. 

When you are doing your self-exam, look out for moles that do not look similar to the ones around them. A troublesome mole might be one that is darker or larger than the ones surrounding it, or it might be smaller or redder than its nearby counterparts. Spotting an "Ugly Duckling" may be a sign that the mole is cancerous, so if you find a spot that looks very different from the spots around it, have a doctor check it out. 

What Else Could it Be? 

There are plenty of types of moles or skin growths that are not cancerous. Most skin tumors aren't dangerous and do not turn into cancer. A typical mole, also known as a nevus, is a common type of skin tumor that isn't cancerous. A Spitz nevus is another type of mole that is often mistaken for a melanoma. Warts are also considered skin tumors, but they are not dangerous, either. Seborrheic keratosis is a black, tan or brown raised bump with a waxy texture that you don't need to worry about. Hemangiomas, commonly referred to as "strawberry spots" or "port wine stains" are also on the list of skin growths that aren't cancerous.