A case of delayed massive hemothorax caused by the rupture of a pulmonary artery pseudoaneurysm after radiofrequency ablation of lung tumors.

Radiofrequency ablation has been applied as a minimally invasive therapy for the local control of lung tumors, including primary and metastatic neoplasms. Hemorrhagic complications after radiofrequency ablation can usually be treated conservatively, but such complications can be massive and fatal in some cases. In this paper, we report the rare case of delayed massive hemothorax caused by the rupture of a pulmonary artery pseudoaneurysm after lung radiofrequency ablation that was treated using transcatheter coil embolization followed by a left lower lobectomy. A 75-year-old woman underwent radiofrequency ablation for the treatment of a metastatic lung tumor in the left lower lobe arising from a colorectal carcinoma located close to a branch of the pulmonary artery. Thirty-six hours later, hemothorax and hemorrhagic shock occurred as a result of a ruptured pulmonary artery pseudoaneurysm and radiofrequency ablation-induced damage to the interlobular pleura. After transcatheter coil embolization of the pulmonary artery pseudoaneurysm, she recovered from a state of shock and a left lower lobectomy was performed. Histological findings revealed the presence of residual tumor cells in the ablated lung tumor. The postoperative course was uneventful, and no evidence of recurrence of the primary disease was seen at 1 year after the surgery. Although hemothorax secondary to the rupture of a pulmonary artery pseudoaneurysm after lung radiofrequency ablation is a rare complication, it should be recognized as a serious potential complication of lung radiofrequency ablation for a tumor located close to the pulmonary artery branch.