Oh Marie, I know this is SO what you did not want to hear! My heart just sank when I read your post. If you feel like screaming, you should go ahead and do that (although you may want to do it out of earshot of your hubby since that might not help HIM).
Then try to calm yourself. BREATHE. BREATHE again. And again. The MRI report gives you more information. It is not the end, it is only information, which will help guide you and your team in deciding what the next step is.
You know that brain mets are treatable - as many on this board have been LIVING with this for years. Christine. StephN. Esther. Others (sorry I can't remember names!).
You didn't mention how large or extensive the brain mets is, perhaps you don't have this information yet.
Check the info on the Her2 home page, the link is below.
http://her2support.org/index.php?option=com_content&task=view&id=44&Itemi d=67
Again, I am so sorry you have this additional wrinkle to worry about. But you now have much more/better information for DFCI than you would have last week.
Please don't give up hope, keep believing.
chris