An abnormal shadow was noted on a chest radiogram of a 61-year-old woman three years ago. This abnormal shadow has changed little over the three years. Examinations changed this year, including chest tomogram, CT and bronchofiberscopy, showed atelectasis of the right S(3) without obstruction of B(3)(a) and B(3)(b). Histologically, a well differentiated adenocarcinoma was found in a transverse bronchial lung biopsy specimen. Postoperative staging was confirmed to be pT(2) NoMo.