The case is a 68-year-old man. He was treated with fourth-line atezolizumab for adenocarcinoma of the left upper lobe of the lung and achieved tumor shrinkage. Hemoptysis began on day 6 of the third course, and he was intubated and ventilated. Angiography revealed that the left bronchial artery and left internal thoracic artery formed a shunt with the pulmonary artery, which was thought to be the source of the bleeding. It is thought that the tumor formed a shunt because it invaded the blood vessel. Transcatheter arterial embolization was performed at the same site and hemostasis was achieved, suggesting that the significant shrinkage of the tumor caused by atezolizumab may have contributed to the massive hemoptysis.
