[A case of cryptogenic organizing pneumonia after postoperative irradiation for breast cancer].

The patient was a 69-year-old woman who had undergone breast-conserving surgery of the right breast, followed by tangential irradiation of 50 Gy to the remaining breast. Her subsequent progress was monitored by endocrine therapy with toremifene. Symptoms consisting of cough and slight fever developed 5 months after completion of radiation therapy. A chest X-ray image revealed an infiltrating shadow in the right middle and lower pulmonary fields, and the patient visited our hospital. BOOP was diagnosed by thoracoscopic biopsy. Spontaneous remission was observed during monitoring of the patient's progress. A shadow subsequently reappeared, for which a steroid was administered. Improvement was rapid. This case suggests that when tangential irradiation with or without endocrine therapy is provided, subsequent to breast-conserving treatment, patients should be monitored for the occurrence of BOOP.