Hi Sassy,
I'm
so sorry you have this dilemma!

But you asked my opinion and here it is. If I were you, I would not take the Tysabri.
Melanoma cells won't necessarily show up in the skin only. I'm not a cancer expert, but I know of someone who was a long time Tysabri user (started with the beginning trials)
and a melanoma survivor from many years previous. That person developed a brain tumor that had mestastisized from melanoma cells. It was a very bad tumor and I don't even know if that person is still alive.
I don't like to bring up this example since there's no way of knowing if it's really a direct result of the Tysabri... but I would want to hear it if I were in your situation.
But as everyone else has said, it's your decision...