Migratory eosinophilic alveolitis caused by radiation therapy

Although radiation pneumonitis is usually confined to irradiated areas, some studies have reported that radiation-induced lymphocytic alveolitis can also spread to the non-irradiated lung. However, there have been few reports of radiation-induced eosinophilic alveolitis. We report the case of a 27-year-old female with radiation pneumonitis, occurring 4 months after radiation therapy for cancer of the left breast. Clinical and radiological relapse followed withdrawal of corticosteroids. Examination of bronchoalveolar lavage (BAL) in patchy airspace consolidations revealed increased eosinophil counts. Finally, clinical and radiological signs resolved rapidly after reintroduction of corticosteroids. Eosinophilic alveolitis may be promoted by radiation therapy. In the present case report, possible mechanisms for radiation-induced eosinophilic alveolitis are also reviewed.