[Intravascular invasion of a thymoma from the thymic vein to the right atrium--a case report].

A 43-year-old woman with a complaint of facial swelling was admitted to our hospital. A chest roentgenogram revealed a mass in the mediastinum. Chest CT and MRI demonstrated a mass in the anterior mediastinum protruding into the superior vena cava (SVC) and right atrium. A diagnosis of thymoma was made by needle biopsy. The patient underwent surgery without preoperative treatment. The tumor extended across the capsule of hte thymic gland and a polypoid growth of tumor reached the right atrium through the lumen of the thymic and left brachiocephalic veins and the SVC. No direct infiltration into the SVC or pericardial cavity was observed. Under cardiopulmonary bypass, the tumor was resected with the left brachiocephalic vein, SVC, and the upper third of the right atrium. The SVC was reconstructed using an EPTFE graft. Histopathologic examination demonstrated a predominantly epithelial cell thymoma. Adjuvant chemotherapy was performed, and no recurrence has been recognized for 3 years postoperatively.