Hi there. My dog Ruby had sudden onset Mast Cell Tumors present about 3 weeks ago. She’s an energetic 4 year old pit/great dane mix (I know because I spent a billion dollars on a DNA kit). I noticed about 7 subcutaneous lumps on her left side while she was outside playing. They felt like little oblong marbles under her skin. Our vet is an hour away. We had moved a few months back and kept our vet because we love him so much. We still see him for routine care. There is a vet very close to our home and I have read good reviews and have had email conversation previously when I was deciding whether or not to switch vets. I was concerned Ruby would have cancer, I just felt it, and didn’t want her to have to make several long trips to our vet if she were to require surgery, etc. So I decided to take her to the new close to home vet. As it is Covid-19 season, I did not get to go inside the vet’s office with her. They aspirated one of the lumps and were concerned. She was scheduled for surgery in the following week. I talked to my other vet about this, and he was not pleased to hear they aspirated her, because he was worried that the histamines from the tumor would cause it to spread. I was alarmed and researched Dr. Google for 2 days. It seemed to me after my research that the aspiration was standard course of care. Ruby had her surgery and had 2 large masses removed. They could not take all of them because there would have been too many incision sites. Directions for care included keeping her inactive for 10-14 days, not an easy dear with an anxious 65 lb lap dog. On day 7 of recovery, I noticed a fluid buildup around the incision site. Back to Dr. Google, I decided she had a seroma. I called the vet the next morning and we took her over and my suspicion was confirmed. They told us to call if it got worse. We still haven’t received the pathology back on the two masses that were removed. This morning I decided I needed to do more research, as two new masses have cropped up (the tumors, not seroma). Ruby is in good spirits and just wants to play and run with our other dogs. She’s mad at me, I’m sure of it, for making her lay around all day. Is it normal to have a seroma after surgery? Why do these tumors pop up all of a sudden?