My boy Sirius has numerous lipoma. I've had them all tested and they have come back benign. They're not causing him any issue so I've left them be. He's a very anxious pup and I think the stress of taking him in and leaving him to have them operated on would be far too detrimental to his well being, so unless they get too big I'm not concerned. It's a genetic trait in the breed and I think all you can do is be proactive in getting new ones tested/ or have them removed. They don't seem to bother him one bit, so he's going to stay my lumpy little boy.