Inflammatory Pseudotumor of the Lung Identified by 18F-Fluorodeoxyglucose Positron Emission Tomography: A Patient Report

The patient was a 71-year-old man with an abnormal shadow on chest X-ray. Computed tomography (CT) of the chest showed a tumor of 38 mm in size in the upper lobe of the left lung S3. A CT-guided lung biopsy was performed, but no malignancy was observed. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) revealed a high FDG uptake in the tumor: the maximum and mean values of the standard FDG uptake in the early phase were 7.3 and 5.3, respectively, and those in the latter phase, 8.3 and 5.9, respectively. The hilar and mediastinal lymph nodes also showed positive for high FDG uptakes. We strongly suspected lung cancer, and performed a left upper lobectomy by video-assisted thoracic surgery. The pathological diagnosis was an inflammatory pseudotumor of the lung: it is a rare disease but often requires differentiation from lung cancer. Literature has been few on FDG-PET about inflammatory pseudotumor of the lung. Differentiation of the disease from lung cancer was especially difficult in the present patient, because both lymph nodes and the tumor showed high FDG uptakes.