I don't think there is any research showing a link between diet and the condition, but I will tell you that my daughter was getting myofibramatosis tumors until she went gluten free (for other reasons), after which she got none for four years. After going to a school where she was getting inadvertently glutened, she began to develop another tumor. She is also casein sensitive, so if you want to err on the side of caution, maybe try a gluten-free or gluten-and-dairy-free diet?