I have never heard of white neoplasms before. They are usually darker in colour. Having said that, there are many forms of skin cancer so I cant be certain. If you are concerned about it, I would agree with Jaz that you should have a doctor check it out.
most likely not. if you have moles that are really dark, theyre the ones you should be worried about. it could just be a halo nevus
youll need to get it checked out by a doctor to find out