Interesting Images18F-FDG PET/CT Imaging of G-CSF–Producing Inflammatory Myofibroblastic Tumor of the PleuraTokunaga, Koji MD, PhD∗; Maeda, Chikara MD∗; Horikawa, Sadao MD, PhD†; Nakayama, Ryuko MD, PhD‡; Umeoka, Shigeaki MD, PhD∗ Author Information From the Departments of ∗Diagnostic Radiology †Respiratory Medicine ‡Diagnostic Pathology, Japanese Red Cross Wakayama Medical Center, Wakayama City, Japan. Received for publication May 26, 2022; revision accepted September 15, 2022. Conflicts of interest and sources of funding: none declared. Correspondence to: Koji Tokunaga, MD, PhD, Department of Diagnostic Radiology, Japanese Red Cross Wakayama Medical Center, 4-20 Komatsubara-dori, Wakayama City, 640-8558, Japan. E-mail: [email protected]. Clinical Nuclear Medicine 48(2):p e84-e86, February 2023. | DOI: 10.1097/RLU.0000000000004457 Buy Metrics Abstract We report a case of granulocyte colony-stimulating factor (G-CSF)–producing inflammatory myofibroblastic tumor of the pleura in a 71-year-old man. Contrast-enhanced CT demonstrated multiple pleural masses with pulmonary hilar lymph nodes swelling. 18F-FDG PET/CT demonstrated marked focal FDG uptake in the thoracic masses with diffuse uptake in the bone marrow. Based on the pathological findings and elevated serum G-CSF level, the patient was diagnosed as G-CSF–producing inflammatory myofibroblastic tumor. Because G-CSF–producing tumors demonstrate aggressive clinical course, early and accurate diagnosis is important. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.