Wow, we had a really funky neuter the other day. The dog had an unusually hard testicle, and we were worried that it might have a tumor inside. He was an older dog, and they can sometimes get testicular tumors if they are not neutered. We started surgery, and it was very difficult to get to the testicle because all of the surrounding tissue was abnormal and thickened. We located the testicle and started to remove it, and suddenly pus started oozing out if it. We had to flush all the pus out of the surgery site. After we removed the testicle The remaining tissues were also very abnormal and thickened . We removed as much as we could and sent it all off to the lab for analysis. Because of all the pus, the dog will have to have a drain in place for a few days and take antibiotics. So here's the deal: Worst case, the dog has a malignant tumor that has spread throughout all the neighboring tissues and possibly internally. Best case, the tumor was confined to the testicle and all of the other abnormal tissue is due to secondary infection and inflammation. Even if this is the case, he still has a lot of healing to do. Moral of the story: Get you dog neutered so that this doesn't happen to him.