[Simultaneous surgical case of thymoma combined and non small cell lung cancer; report of a case].

We described a case of simultaneously treated thymoma associated with lung cancer, with reference to previous reports. A male in his forties who was pointed out a mediastinal mass and a nodular shadow in the right lower lung field on chest X-ray was admitted to our hospital. The resection of right lower portion of thymus and right lower lobectomy of the lung were performed. The mediastinal mass appeared to be a thymoma. Although thymomas associated with lung cancer are uncommon, the relationship between thymomas and the incidence of nonthymic malignancy is discussed in several papers. Since lung cancer is increasing in our country, thymoma associated with lung cancer are expected to increase.