Preheat oven to 425 degree F. In a Dutch oven cook pasta according to package directions. Drain well; return to pan. Meanwhile, in a bowl combine pesto, Alfredo sauce, and milk. Add to pasta, stirring gently to coat. Gently fold in tuna.
Transfer pasta mixture to a 2-quart oval baking dish. Sprinkle with shredded Parmesan cheese. Bake for 10 to 15 minutes or until heated through and cheese is just melted. Makes 6 servings.