I love a happy story.
We had something very similar happen with our Shepherd when I was a kid. Someone broke in through the kitchen, and opened the door to the summer porch where our German Shepherd Tasha stayed when we were away. We found a big chunk of shirt and a fair amount of blood.
A few days later my brother mentioned that one of his "friends" was sporting a rather nasty arm injury that looked a lot like teeth.
My guess is the ahole tried to break in to find my brother's drug stash and didn't find what he was looking for.