[A case of invasive thymoma responsive to preoperative chemotherapy].

A 38-year-old male was admitted with edema of the neck and face. Chest X-ray revealed a mediastinal tumor. On chest CT and MRI, a tumor infiltrating the superior vena cava and bilateral brachiocephalic veins in the upper mediastinum was observed. Venography revealed obstruction of bilateral brachiocephalic veins. The tumor was diagnosed as thymoma by percutaneous biopsy, but since it was of stage III according to Masaoka's classification, complete extirpation was considered to be impossible. Preoperative chemotherapy with multiple drugs (CDDP, ADM, VCR, CPA) was administered. The superior vena cava syndrome resolved and the tumor diminished in size. Because of leukopenia, rhG-CSF was also used. The tumor infiltrated the left brachiocephalic vein; therefore, total resection and left brachiocephalic vein reconstruction were performed. Histopathological examination showed extensive, necrosis and fibrosis containing residual thymoma. Postoperatively, similar chemotherapy and cobalt irradiation (40 Gy) to the superior mediastinum were performed. We thus present a case of invasive thymoma which responded to preoperative chemotherapy.