[Needle tract implantation of thymoma after transthoracic needle biopsy].

A 53-year-old man was admitted to hospital because of an anterior mediastinal mass. For definite diagnosis, needle biopsy was performed under ultrasonic examination. The histopathological diagnosis was thymoma and thymo-thymectomy was performed. The tumor recurred in the right anterior chest wall 10 years later. It is suggested that the thymoma tissue had been implanted in the needle tract. To our knowledge, this is the 2nd reported case of thymoma which has been implanted in the needle tract.