Avascular necrosis of bilateral femoral head as a result of long-term steroid administration for radiation pneumonitis after tangential irradiation of the breast.

We report a patient with avascular necrosis of the bilateral femoral head resulting from long-term steroid administration for radiation pneumonitis that occurred after tangential irradiation of the breast. The patient was a 50-year-old postmenopausal woman with breast cancer, stage IIIB (T4bN0M0) in the right C area. Following wide excision of right breast carcinoma and level III axillary lymph node dissection, whole-breast X-ray irradiation was given, at a dose of 2 Gy per fraction; the total dose was 50 Gy. On day 84 after the initiation of radiation therapy, she developed radiation pneumonitis. As the lung shadow expanded to the contralateral lung, she received steroid medication. Despite the steroid medication, the symptoms were exacerbated; therefore, she underwent steroid pulse administration with subsequent oral steroid medication. She improved immediately, but subsequently the radiation pneumonitis relapsed three times when the steroid medication was stopped. The period of medication was 423 days and the cumulative amount of steroids was 7365 mg before complete resolution occurred. In the 19 months after she stopped the steroid administration, she developed avascular necrosis (AVN) of the bilateral femoral head. This was regarded as a complication of the steroid treatment. Patients treated with long-term or high-dose steroid administration have been suggested to be at great risk of developing AVN, but this hypothesis remains controversial. The probability of AVN occurrence may be very small, but it should be considered as one of the complications of steroids, which are often used to treat radiation pneumonitis.