A 56-year-old man, at one year before his first visit to our hospital, had presented cough, stridor and chest pain, and expectorated a mass, resulting in prompt disappearance of the symptoms. He was afflicted with recurrent symptoms, and the bronchoscopy showed a polypoid tumor occluding the right lower bronchus. The tumor was resected via bronchoscopy, which revealed histologically small cell carcinoma with significant inflammation and scar formation. The tumor was macroscopically the same as the one that had been expectorated by the patient at one year previously. A right lower lobectomy was conducted, but the specimen demonstrated no residual tumor. Tumor invasion into the bronchial wall was therefore limited within the submucosal layer for more than a year. Finally, the present tumor was diagnosed as an early small cell lung cancer with a characteristic of self involution. With no adjuvant treatment, the patient is well without tumor recurrence at 3 years to date after the surgery.