Oh, dear. I hope it isn't cancer, or if it is, that a simple (okay, not so simple) amputation will eliminate it. I have known several 3-legged dogs, and they all adjusted amazingly well.

My Dad lost Bruni, our family's most recent Saint Bernard, to lymphoma at 8 1/2 years old. It's sad, but they tend to hide any hurts from us for far too long. I hope your Boo Boo will be okay.