My mom had an appt today with her oncologist now he is telling her she may have brain cancer .... he is sending her for an emergency MRI tomorrow...why would a physician put that out there before he even has information to back that up..... I'm really not understanding how this works I guess PET scan shows one spot on lung, biopsy showed all benign prior to scan. Now brain cancer? It is possible to have brain cancer and a 2.5cm mass in your lung without it being other places in your body?