1999 Mitsubishi Galant spark plugs

We were installing spark plugs and while screwing them in (they were just barely into the threads) the ceramic part (including the nut) broke off of the medal casing on the bottom.

I have no clue how to get this back out without removing the entire head...

any suggestions?
[img:298feaa355]http://www.2carpros.com/forum/automotive_pictures/325511_4194_1.jpg[/img:298feaa355]