[Radiation pneumonitis resembling bronchiolitis obliterans organizing pneumonia after postoperative irradiation for lung cancer: a case report].

We report a case of BOOP-type pneumonitis after postoperative irradiation for lung cancer. A 60-year-old woman with adenocarcinoma in the right lung underwent lobectomy followed by radiotherapy of 50.4 Gy. After a shadow of typical radiation pneumonitis was resolved in the irradiated site, two relapses, in which migratory infiltrative shadows appeared outside the radiation field, occurred at 6 and 12 months after the completion of radiotherapy. These shadows disappeared spontaneously at 10 and 18 months after the completion of radiotherapy. The radiological findings and clinical course suggested that BOOP-type pneumonitis was the most likely diagnosis for these lesions. This type of lung damage after radiotherapy of the thoracic region should be identified and properly treated.