Well from what I've heard benign tumors won't harm your snakes at all. But then again some say the malignant ones will. Some how I can't find the possibity for snake to eat a mouse with a malignant tumor getting harmd. from it. Just as long as you don't cut it open. well any tumor like that to be exact. but if your worried, either ask yor local vet if it's okay to do so, or be on the safe side and just don't feed them it. But thats just MHO.