A case of mediastinum teratoma diagnosed as congenital hemophilia B due to postoperative bleeding

<p>Congenital hemophilia is a congenital bleeding disease caused by a decrease in the activity of clotting factors. The two common types of hemophilia are: hemophilia A, characterized by decreased factor VIII activity, and hemophilia B, which results from decreased factor IX activity. In 2020, the total number of hemophilia B patients living in Japan was about 1,200; therefore, it is an extremely rare disease.</p><p>We report the case of a 17-year-old man diagnosed with an anterior mediastinum tumor of 10 cm in diameter. Imaging studies suggested that the tumor was a mature teratoma. A preoperative blood test revealed a slightly prolonged activated partial thromboplastin time (APTT) of 47 seconds. Although postoperative hemorrhage was observed after a tonsillectomy performed at the age of 12 years, there was no other history of bleeding disorders. The tumor was resected through hemi-clamshell thoracotomy. Bloody drainage fluid and dyspnea were observed on the second postoperative day. Chest CT revealed bloody pleural effusion, atelectasis in the left thoracic cavity, and a hematoma on the posterior of the sternum. A second operation was performed for postoperative bleeding, and bleeding from the posterior surface of the sternum was confirmed. Hemostasis was achieved using an electric scalpel, and no further bleeding was observed after the reoperation. He was diagnosed with congenital hemophilia B because factor IX activity decreased.</p><p>Here, we report a case of congenital hemophilia B diagnosed due to postoperative hemorrhage following the removal of a mediastinum teratoma.</p>