Bilateral Diffuse Radiation Pneumonitis Caused by Unilateral Thoracic Irradiation: A Case Report

Radiation therapy is one of the most important therapeutic modalities for the treatment of lung cancer. Radiation pneumonitis is one of the important complications associated with radiotherapy for lung cancer. Radiation pneumonitis is generally limited to the irradiated lung and is manifested by the insidious onset of dry cough, dyspnea, and mild fever, resulting in damage and edematous changes of alveolar structures on histologic inspection. Clinically, diffuse bilateral radiation pneumonitis accompanied with acute symptoms after unilateral thoracic irradiation appears very rarely. Histopathologic examinations for the diagnosis of out-of-field radiation pneumonitis are rarely performed. We herein describe a case of extensive bilateral radiation pneumonitis which developed acutely after salvage radiotherapy for squamous cell carcinoma in the left upper lobe of the lung. The condition was confirmed by a diagnostic help of histopathologic findings. (J Lung Cancer 2012;11(2):97 101)