Three modalities need to come together to make sure that you have an accurate diagnosis, of whether you have skin cancer or not. The first step is an examination by a dermatologist. Oftentimes, just with the naked eye a dermatologist can determine, whether a mole or a suspicious bump is cancerous or completely benign. The next step is the use of dermoscopy.
Dermoscopy allows us to utilize polarized lights to look at the mole in more detail. Different shades of color, blood vessels, certain types of scar-like tissue can be examined better with a dermoscope, and give us a better idea of whether a bump is cancerous or not. The final step is a skin biopsy. A skin biopsy is the only way to tell us 100% definitively, whether we have skin cancer or not.