For the pasta salad, cook the penne in salted water until al dente.
Drain and allow to drain. Drain tomatoes and cut into small pieces. Wash arugula and mushrooms and cut mushrooms in half. Peel and chop garlic.
Heat oil in a pan and sauté mushrooms. Add garlic. Salt and pepper everything. In a bowl mix pasta, tomatoes, mushrooms, arugula and olive oil.
Season again with salt and pepper and garnish with balsamic vinegar.