[Recurrence of a stage I thymoma after resection].

A 61-year-old man had a non-invasive thymoma. The tumor recurred in the aortocaval groove 6 months after thymothymectomy. The second tumor was a non-invasive, lymphocytic thymoma with polygonal cells, and was similar to the first one. The tumor may have been a multicentric thymoma, with malignant cells remaining in thymic tissue behind the brachiocephalic veins. To resect thymomas, extended thymectomy should be done to prevent recurrence from the remaining thymic tissue. CT scans should be obtained for long-term follow up after surgery, to detect any recurrence in its early stage.