Migratory eosinophilic alveolitis caused by radiation therapy

The lung is one of the most radiosensitive organs, yet is frequently irradiated during treatment for thoracic malignancy. Radiation-induced lung injury often results in radiation pneumonitis and radiation fibrosis. Radiation pneumonitis becomes apparent at about 1 to 6 months after radiotherapy and fibrosis after at least 6 to 12 months. The association between pneumonitis and the development of fibrosis is still uncertain (1-4). Classically, the pathological and radiological changes caused by radiation are confined to the irradiated area. However, several reports have described an intense lymphocytic alveolitis not only in the irradiated lung but also in the non-irradiated lung. These changes have been demonstrated by diffusely increased gallium uptake, lymphocytosis in bronchoalveolar lavage (BAL) from non-irradiated lung, and a histologic pattern of organizing pneumonia from the migratory opacities (3,5-11)