The most common type of lung cancer that can cause pulmonary tethering is adenocarcinoma of the lung, which is the most likely type to cause pulmonary embolism. The cause is relatively due to the fact that lung cancer such as adenocarcinoma of the lung can reach the arteries or veins of the lung through the lymphatic as well as blood circulation, thus causing obstruction and triggering pulmonary embolism. In addition, adenocarcinoma of the lung can cause blood clotting disorders and increase the viscosity of the blood.