Hi. It is my understanding that low b12 can cause the symptoms of MS. As far as causing enhancing lesions, I don't know. (I don't think so) I do not believe that low thyroid can cause lesions, but can make you very tired. Sorry I can't be of more help.
What are your symptoms?
I hope that's not the case.
I am not sure but I do know you can have MS and other things at the same time.
Alex