Cook pasta in lightly salted water according to package directions, adding frozen vegetables for the last 4 minutes of cooking. Drain and return to pan.
To the pasta add 1/4 cup of the milk and the cheese. Cook and stir over medium heat until cheese is melted and pasta is coated, adding additional milk as needed to make of creamy consistency. Gently fold in tuna; heat through. Season to taste with salt and pepper. Makes 4 servings.