The first two BSC that I had removed presented in the 'usual' way- ie: spots that did not clear up. First one on the side of my nose, close to the eye, required plastic surgery when removed.
However, the third time was no spot, but just a very small patch of light coloured skin on my forehead. When I first went to GP with this I saw a newly qualified doctor who dismissed me out of hand. I made him check with his mentor at the surgery who agreed that due to my history this required checking out by a dematologist.
Even she was perplexed, but took a small (two stitches), biopsy. When I went to the hospital for the result I was expecting to be sent away, but they said it was positive and required taking away then and there. It turned out this was the worst of those I had, going downwards instead of outwards, and I left nearly an hour later with eight stitches in my forehead.
When I had these stitches eventually removed I asked what would happen if I ignored these in the future. Nurse told me that they are ulcers, so I would end up with a large hole.
Have since gone some ten years with no re-ocurrance, now this tiny white spot right on tip of my nose. I have appointment to go to Dermatology in a couple of weeks time. They have this marvellous special camera which takes a photo instead of having to do a biopsy and can tell from that everything they used to learn from biopsy.