Anyone hear of “Benign MS”?

I was diagnosed in 2006 with just weakness in my left arm. Brain MRI found a lesion and started on Copaxone. Yearly brain MRIs until 2010 with no new Lesions. So my doctor changed to every three years MRI. But then I had to change doctors and she finally did a spine MRI and found a lesion however they don’t know if that was there from the beginning because I never got a spine MRI before that. Now in 2023, doctor left so so have another new Doctor. This new Doctor says now since I haven’t had any relapses or exacerbations since my first diagnosis, it could be something called “Benign MS”. In the almost 20 years since my diagnosis, that is the first I’ve ever heard of that. Is this something new that was discovered?