[Thymoma with synchronous pulmonary metastasis; report of a case].

We report a resected case of thymoma with a solitary pulmonary metastasis. A 63-year-old woman had pointed out a solitary nodule in right lung field on chest X-ray. Computed tomography (CT) scan showed an anterior mediastinal tumor and a solitary lung nodule in the right lower lobe. Extended thymectomy and partial resection of right lung was performed. Pathological diagnosis showed an invasive thymoma (type B3) and a pulmonary metastasis. Post operative radiotherapy was administered and she is doing well 19 months following the resection. Thymoma with a solitary synclonous pulmonary metastasis is rare and is classified into Masaoka stage IVb. Generally, thymoma cases with distant metastasis are not indication for operation. But, if radical resection is possible, operation is recommended for good prognosis.