Synchronous organizing pneumonia after sequential three-dimensional radiotherapy for three lung metastases from hepatocellular carcinoma: a case report
Radiation-induced lung injury can be categorized into radiation pneumonitis (RP) and organizing pneumonia (OP). Differences between RP and OP have been reported in terms of the time to appearance, predictive factors, expression mechanism, and migration of lung infiltration. However, no author has demonstrated the time to OP appearance after sequential radiotherapy for lung tumors in the same patient. We describe woman in her 70s with lung metastases developed OP synchronously after sequential three-dimensional radiotherapy (3D-CRT). A woman in her 70s who had received 3D-CRT sequentially for three metastases in the left lung from hepatocellular carcinoma (HCC). We administer 3D-CRT for metastases in the left upper lobe. Three months after the end of 3D-CRT, there were no changes outside or inside the radiation field on chest radiographs and computed tomography (CT). We decided to administer 3D-CRT for a second time due to metastasis to the lower lobe. At 1.5 months after the end of the second 3D-CRT course, the patient presented with dry cough, at 2 months from the second radiotherapy cycle, dense pneumonic infiltrates with air bronchograms within the first and second radiation fields and outside the field was synchronously detected. A diagnosis of lung injury, most probably OP, due to radiotherapy was made. This case report draws attention to the development of synchronous OP after sequential radiotherapy and advises careful follow-up with the initiation of a second radiotherapy cycle even if OP does not appear for several months after the first radiotherapy cycle.