Residence stamp to PR. Need help!!

Hello guys, I really need info about the following issue, and hope you can help me out on this one:
I am a non EEA married to my Italian citizen wife for 14 years now. \
we moved in to the Uk in 2010, and i got my Residence stamp in 2010 as well.
next january 18,2016 my 5 year resident visa will expire,and i will of course apply for my PR. question is:
can i travel abroad with m y wife and return after my residence visa is expired? we plan to go to Brazil on january 20th and return a month later (my residence stamp expires in january). So,can i get in the uk normally with my italian wife? some told me its ok, and some said it might be some hassle but we are settled here and its ok....please clarify.

i really appreciate your help!
thanks a lot!