[A case of multiple colon cancer appeared after thymectomy for thymoma with myasthenia gravis].

A 62-year-old woman was admitted to our hospital because of diarrhea and melena. Thymectomy for thymoma with myasthenia gravis was carried out on this patient four years ago. Barium enema revealed four tumor shadows in the ascending and transverse colon. Multiple colon cancer was diagnosed and extended right hemicolectomy was carried out. The postoperative course was uneventful and she has been free from any symptom. In this paper, we discussed the relationship between thymoma and the incidence of nonthymic malignancy.