[Case of loxoprofen sodium-induced eosinophilic pneumonia that occurred ipsilaterally after VATS lobectomy for lung cancer].

A 76-year-old man was admitted because of dry cough and dyspnea two weeks after VATS lobectomy for lung cancer. Chest radiographs and computed tomography showed interstitial shadows in the only operative lung side. Although antibiotic drugs were given because we believed it to be postoperative pneumonia, abnormal shadows on chest radiographs increased. A bronchoalveolar lavage fluid (BALF) study performed on the 21" day after operation showed that the proportions of eosinophils, basophils and mast cells had increased, and the CD4/CD8 ratio was 4.42. The drug lymphocyte stimulation test for loxoprofen sodium was positive. Based on the clinical course, laboratory data and BALF study, we arrived at a diagnosis of drug-induced pneumonia caused by loxoprofen sodium. Treatment with corticosteroid resulted in marked improvement of the chest radiographs and clinical findings. Drug-induced pneumonia usually occurs bilaterally, but it occurred only on the operative side in this case. Although rare, it is important to recognize that unilateral drug-induced pneumonia is one of the differential diagnose of postoperative pneumonia.