Ive killed a few deer with these same things...pretty common in southern Utah. Fish cop told me its from infection to an injury or tick. They are solid masses...Ive dissected and solid all the way through. I shout about a 6 year old buck a few years ago and it had one the size of a cantaloupe!
"I'll see you all this coming fall in the Big Rock Candy Mountains!"
not very appealing are they? do they affect meat? id have a hard time shooting an animal that had one of those on them, then again maybe they need to be culled??? not sure.