Diagnostic Value of 18F-FDG PET/CT in Patients with Suspected Paraneoplastic Syndrome
Esra Çiftçi11Department of Nuclear Medicine Sakarya University Research and Training Hospital Faculty of Medicine, Sakarya, Türkiye
Objectives: To evaluate the diagnostic value of 18F-FDG PET/CT in patients with suspected paraneoplastic syndrome who present with unexplained elevation of acute-phase reactants (APR) and constitutional symptoms. Methods: In this retrospective, single-center study, 102 adult patients who underwent 18F-FDG PET/CT from June 2018 to April 2025 for suspected paraneoplastic syndrome were included. All had unexplained elevated APR with or without constitutional symptoms after initial evaluation. PET/CT findings were categorized as suggestive of malignancy, infection, inflammatory/rheumatic disease, or negative. Final diagnoses were based on histopathology, microbiology, clinical criteria, or ?6 months of follow-up. Results: Malignancy was the most common final diagnosis (n=48, 47.1%), followed by inflammatory/rheumatic diseases (n=33, 32.4%). 18F-FDG PET/CT had 100% sensitivity and negative predictive value for detecting malignancy, with no false negatives. Specificity was 29.6%, and positive predictive value was 55.8%. Of 38 PET-positive, malignancynegative cases, 28 (73.7%) were rheumatologic or inflammatory diseases, mostly polymyalgia rheumatica and vasculitis. Patients with both elevated APR and constitutional symptoms had a significantly higher risk of malignancy than those with isolated APR elevation (OR =12.33; 95% CI: 3.3–45.8; p=0.001). Conclusion: 18F-FDG PET/CT is highly sensitive for detecting cancer in patients with suspected paraneoplastic syndrome and unexplained inflammation. Keywords: Constitutional symptoms, Paraneoplastic syndrome, Positron emission tomography computed tomography
Cite This Article
Çiftçi E. Diagnostic Value of 18F-FDG PET/CT in Patients with Suspected Paraneoplastic Syndrome. EJMI. 2026; 10(3): 392-398
Corresponding Author: Esra Çiftçi