Is This Common
This giant puffball mushroom is in our back yard.. It's 48" around!
Kent County Michigan mushroom identification
Although we can't comment on the identification of this mushroom (see http://msue.anr.msu.edu/news/identifying_mushrooms_there_is_more_to_it_than_you_might_realize) Mushrooms of this size are not uncommon.
Sorry we can't be of more help,