[A case of thymoma with thymic cyst]

A 43-year-old man was pointed out an abnormal shadow on chest X-ray film. Chest CT showed a solid mass and a cyst at anterior superior mediastinum. Operation revealed a capsulated thymoma and a multilocular thymic cyst. PTH and CA19-9 level in the cystic fluid was elevated. Histological examination demonstrated the clear separation of the mixed type thymoma and the thymic cyst. There were few reports for cases of thymoma with a thymic cyst.