[An autopsy case of invasive thymoma extending to the right atrium with superior vena cava syndrome as the initial manifestation].

We report a case of invasive thymoma presenting with superior vena caval obstruction and intracardiac extension. A 74-year-old man was admitted in July 2002 with swelling of the face and right upper extremity. Computed tomography of the chest revealed a small anterior mediastinal mass, which infiltrated the lumen of the superior vena cava extending into the right atrium. Invasive thymoma was strongly suspected, but he refused any medical treatment. His health declined steadily, with repeated right-sided heart failure. He died due to cardiac tamponade 50 months after his first visit. On autopsy, the tumor was diagnosed as a thymoma classified as type B3 according to the WHO histological classification. Formation of a tumor thrombus in the superior vena cava and the right atrium is a rare mode of extension of thymoma. In this respect, our case may be valuable for improving the understanding of the natural course of invasive thymoma.