[Organizing Pneumonia with High Radiotracer Concentration on Fluorodeoxyglucose-positron Emission Tomography, Mimicking Pleural Dissemination of Lung Cancer;Report of a Case].

A 68-year-old man was referred to our hospital because of an abnormal shadow in the chest roentgenogram. Chest computed tomography (CT) showed the nodule in the right upper lobe (S3), 17 mm in size. One month later, fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT scanning revealed positive reaction in the right upper lobe lesion and new lesion close to another lobe. In addition, interloblar small nodules were detected, 5 mm and 7 mm in size. A transbronchial brush cytology by bronchoscopy was performed, and the microscopic findings demonstrated the presence of atypical cells, suspected adenocarcinoma. The video-assisted thoracoscopic surgery was performed to establish a diagnosis and a treatment. Histopathological examination showed no malignancy and organizing pneumonia with inflammation. In case of the PET-positive solitary nodule increasing in size, organizing pneumonia should be included in the differential diagnosis.