Neural Tumor/Neurofibramatosis ?

This is kind of a two part question...
First, I have a 'soft tissue tumor of neural origin' in my right axilla (armpit) - apparently part of the brachial plexus. It is large - 4 x 3 x 2.8 cm - and growing fairly quickly (in 2.5 weeks it grew .8 cm in one dimension). It 'looks' benign on the MRI, with circumscribed margins, although the doctors agree it must come out because it's not stable. It is effecting my fingers/hand now (electric shocks). It is also getting painful. I am worried both about the surgery and the possibility it may be cancer. I'm probably going to have to go out of the area to get this surgery done, and have no idea what to expect - hospital stay, recovery time, permanent damage (they have said there will be at least some permanent damage to my nerve). It is possible they may have to do a nerve graft if the tumor is in the fibers. Neurofibroma and schwannoma have been mentioned several times.

Also, yesterday while talking to my grandmother, she informed me my late grandfather had this EXACT same problem. I know NF1 is inherited... But I had told all my dr's it didn't run in my family... Because (of course) no one told me! Of course, my dad (his son) has not had any issues with neural tumors (although I don't think there's been reason to check anyway).

Anyone have any advice on prep for surgery? What to expect - hospital and post-surgery use/damage? Should I mention my grandfather's issues to my dr? Is cancer even a real concern with these things?

I'm sorry this is such a scattered question. Up until a week/two weeks ago, my doctors were thinking it was a lymph node, and now it's this, and there's not near as much info about neurofibromas as I would expect. Plus I'm burned out on researching when every test changes the whole ball game.

Thanks for getting through that jumble... I apologize again for my fried brain.

Katie