経過観察時に18F-FDG PET/CTで原因不明の偽陽性がみられた下顎骨悪性腫瘍の1例

• Published in: Shika Hoshasen Vol. 57; no. 1; pp. 46 - 48
• Main Authors: 秋山, 広徳, 森, 悠衣, 清水谷, 公成, 蒲生, 祥子
• Format: Journal Article
• Language: Japanese
• Published: 特定非営利活動法人 日本歯科放射線学会 2017; Japanese Society for Oral and Maxillofacial Radiology
• Subjects: 18F-FDG PET/CT; false positive; recurrence of malignant tumor; フルオロデオキシグルコース-陽電子放出断層撮影/コンピュータ断層撮影; 偽陽性; 悪性腫瘍再発
• ISSN: 0389-9705; 2185-6311
• DOI: 10.11242/dentalradiology.57.46

False-positive findings are sometimes observed on 2-deoxy-2-［18F］ fluoro-D-glucose （18F-FDG）-positron emission tomography （PET）/computed tomography （CT） images. They can be caused by skeletal muscles after exercise, tissues suffering from active inflammation, and tissue near to dental crowns. Herein, we report a rare case in which false-positive findings were seen on 18F-FDG PET/CT images, and none of the abovementioned causes applied. A 61-year-old male had undergone six 18F-FDG PET/CT examinations during the follow-up period after mandibular resection for gingival carcinoma, one of which produced negative results, and the rest produced positive results. Clinical examinations and CT and magnetic resonance imaging scans did not obtain any findings that were indicative of a tumor or inflammation. There were no differences in the 18F-FDG PET/CT imaging conditions between the scans that produced positive and negative results. We were not able to identify the cause of the false-positive findings. It is important to use multiple imaging modalities and physical examinations to diagnose recurrent malignant tumors.