Abstract
BACKGROUND: Rupture of a thymoma is rare, and due to its rarity, the mechanism of rupture remains unclear. Here we report a case of a ruptured thymoma that ruptured due to an increase in the intratumoral pressure caused by recurrent hemorrhaging. CASE DESCRIPTION: A 70-year-old woman presented 2 days prior persistent right chest and shoulder pain. A chest computed tomography (CT) scan revealed the presence of a mass occupying the anterior mediastinum and a right pleural effusion. It was diagnosed as an anterior mediastinum tumor. The increase in the levels of inflammatory markers and tumor necrosis observed on CT were suggestive of infection. As the general status of the patient was stable and she initially received antibiotic medical therapy, an improvement in the inflammatory marker levels was observed with antibiotic therapy. A surgical resection was performed 10 days after admission. Median sternotomy revealed a tumor extending from the mediastinum to the right thoracic cavity. Since the adhesion was strong and tumor invasion was suspected, the tumor was completely resected by combining a partial resection of the right middle and lower lobes with the pericardium. Pathological examination revealed that the tumor was a type B2 thymoma with fibrosis, necrosis, hemosiderosis, and hemorrhaging, suggesting recurrent hemorrhaging within the tumor. CONCLUSIONS: Based on the findings of our case, recurrent hemorrhaging within the tumor led to an increase in the intratumoral pressure and chronic inflammation and necrosis weakened the tumor wall. These changes contributed to the subsequent rupture.