Left brachiocephalic vein-remember-the thymus is a very superficial structure found in the anterior mediastinum. the left brachiocephalic vein courses through the mediastinum to join the right brachiocephalic vein and form the superior vena cava on the right side of the thorax. since the left brachiocephalic vein is fairly superficial, it travels just deep to the thymus. so, it might be compressed by the tumor. see netter plate 206 for a picture of the thymus and the left brachiocephalic vein.
the left pulmonary vein, left bronchial vein, and right pulmonary arteries are deep structures that enter and exit the lung at its root-they are not near the thymus. the right superior intercostal vein drains intercostal spaces 2-4. it drains into the arch of the azygos vein and is not associated with the thymus.