Migratory bronchiolitis obliterans organizing pneumonia after unilateral radiation therapy for breast carcinoma

We report the case of a 59 year old woman who developed cough, dyspnoea and fever with patchy migratory airspace infiltrates, 2 months after right breast radiation therapy for breast carcinoma. Lung infiltrates were initially localized in the irradiated area and spread to the contralateral lung. Lung biopsy, performed in an unirradiated area of the contralateral lung 9 months after completion of radiotherapy, revealed a typical histological pattern of bronchiolitis obliterans organizing pneumonia. No cause of bronchiolitis obliterans organizing pneumonia other than radiation was found. Treatment with corticosteroids resulted in rapid clinical improvement and complete resolution of airspace opacities. This case suggests that localized lung irradiation might trigger the development of a bilateral lung disease, with a histological pattern of bronchiolitis obliterans organizing pneumonia.