One of my girls has a large tumor on her side. It's almost golf-ball sized now as she's had it for many months. It is harmless, other than being in the way, so I've gone by the motto "if it's not hurting her then let it be." So far she has remained perky and playful. If I could have it removed for $20, I would definitely do it. I havent taken her to a vet yet because I was certain it would be WAY more than that. I'll have to call around now.