I've got an eight year old yellow lab. A few weeks ago I discovered a tumor on his back, took him to the vet, and a biopsy determined that it is a harmless (benign) lipoma. OK no worries. Then, tonight, I discovered four additional small masses that appear to be attached to the subcutaneous layer (I say that because they move with the skin). I believe that they are also lipomas because they are identical to the original tumor in ever respect other than size. What the hell is going on?? Should I be worried? Also, do I need to have each of the additional masses tested for malignancy?