I bred a litter of Great Pyrenees puppies and the litter seemed fine & healthy. At 8 wks of age they received their vet checks & vaccines with a clean bill of health. Shortly after this appointement I started the litter on Revolution, still all fine & healthy. Approx 3wks later (during a bath) I noticed one of the pups had a golf ball size lump growing on her upper thigh (buttock) and a smaller, less noticeable lump starting on the other side as well, no pain or discomfort ... what could this be ??????????????