Said woman should not panic or jump to conclusions, but SHOULD call a gynecologist's office (either the one she saw two years ago or perhaps one a friend or family member recommends) and make an appointment immediately. The woman should make sure she sees him or her right away to clear up the mystery once and for all.
Asking a bunch of strangers on an Internet chat forum whether or not she has breast cancer is really not the way to go.
Call a doctor, make an appointment, get it done. You need a checkup anyway, so it's a win-win and you'll get the information you need--and probably some peace of mind.