Our dog had a tumor that was benign.  She got it when she was about eight years old and it was in the stomach region.  It did not impede her movements and never seemed to bother her.  We had it checked at every vet visit we made.   Over time it began to grow, and when it did, it became too large to be removed surgically without injuring her other organs.  We lost her, and we wondered if we had been to careless in thinking that just because the tumor was benign, it was not a problem.   I don’t know the location of your pet’s tumor, but I suggest that you keep a vigilant eye to make sure that it is not getting larger.  If it does begin to increase in size, please see your vet immediately and ask if perhaps removal isn’t the safest way to proceed.