The authors describe a case of a woman submitted to radiation therapy for breast carcinoma who presented, 40 days after the end of the treatment, fever, dry cough, dyspnea on exertion, and weight loss. Chest imaging revealed migratory opacities. The histopathological examination of transbronchial biopsy specimens showed characteristic findings of BOOP. Corticosteroid therapy resulted in dramatic clinical improvement, together with complete clearing of the pulmonary opacities on chest imaging. The authors present a brief review of the literature concerning radiation-induced lung injury, emphasizing the importance of including BOOP in the differential diagnosis in these complications. The present case, as well as the two other reports from the literature, provide further evidence for the role of irradiation injury as a cause of clinicopathological syndrome identical to idiopathic BOOP, i.e., radiation-induced BOOP.

Keywords: Bronchiolitis obliterans organizing pneumonia. BOOP. Radiation pneumonitis. Radiotherapy. Breast carcinoma.