I had an emg&ncs, with wasting in right hand apb and arm, weakness in rightside, cachectic, neuro called and said it might be small cancer but which one? 26yo f, epileptic controlled since 2009?

I have no idea. Call the Neurologist. I have not mastered reading other Drs minds on the internet yet. But small cancer is of not help.

Have NO clue what kind of cancer you might have if this is a correct diagnosis, and have insufficient information to draw any conclusions from your post. Suggest, instead, you handle this via a more thorough approach, a virtual consult (www.connect@healthtap.com)