Abstract
This report represents one case of infiltrative thymoma followed by squamous cell carcinoma of the lung. A 69-year-old man suffered from infiltrative thymoma which reduced by the radiation therapy. Seven years later its relapse and the onset of squamous cell carcinoma were found simultaneously. Infiltrative thymoma metastatized not only to mediastinum but also to liver and bronchus. Squamous cell carcinoma developed in the right upper lobe. In spite of chemotherapy against them, the patient died.
There are many cases in which infiltrative thymoma is accompanied by squamous cell carcinoma of the lung simultaneously, however, secondary onset of squamous cell carcinoma after the radiation therapy of infiltrative thymoma is rare.
Secondary carcinogenesis of this case was considered to be closely related with immunological abnormalities caused by thymoma, effects of radiation, smoking and so on.
