Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally, until tender yet firm to the bite, about 8 minutes.
Meanwhile, drain olive oil from tuna can into a skillet over medium-low heat. Cook green onions and mushrooms until softened, 2 to 3 minutes. Add cream cheese and stir to combine. Reduce heat to low and stir in yogurt and lemon juice. Mix in sweet corn and drained tuna until well combined. Season with pepper. Drain pasta, add to the skillet, and mix to combine.
