Cryptogenic organizing pneumonia after radiotherapy for breast cancer.

We report a case of lasting fever and cough with pulmonary infiltrates progressing 4 months after adjuvant radiotherapy following surgery for breast cancer. Chest radiography and computed tomography demonstrated alveolar opacities outside the irradiated pulmonary area. Laboratory data revealed neutrophilia and increased levels of C-reactive protein. Bronchoalveolar lavage fluid displayed increased lymphocyte counts, and transbronchial lung biopsy revealed histological patterns compatible with cryptogenic organizing pneumonia (COP). Corticosteroid therapy resulted in marked clinical improvement. From the histological and clinical findings, this case was judged to be a case of COP induced after radiotherapy for breast cancer, similar to those reported recently.