Pitfalls of 18F-FDG-avid PET-CT in the vocal cord: variation in the glucose metabolic patterns

Abstract Background Integrated positron emission tomography/computed tomography (PET/CT) using 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG PET/CT) is an invaluable tool for assessing glucose metabolism and providing detailed anatomical imaging in oncologic evaluations. However, interpreting 18F-FDG PET/CT remains challenging, especially because FDG has non-specific uptake in both benign conditions and malignancies. Aim of the work This report highlights the importance of understanding the mechanisms behind FDG accumulation in the vocal cords. We present three clinical cases where tumours, inflammatory processes, and normal tissue environments are often indistinguishable. Case presentation Case 1: 42-year-old man with 2 weeks of hoarseness and a left upper-lobe FDG-avid lung mass (T3N2M0). CT showed an atrophic left vocal cord; PET demonstrated compensatory increased FDG uptake in the right vocal cord (SUVmax 5.01). Case 2: 63-year-old diabetic woman with weight loss and nocturnal fever; chest CT suggested chronic changes consistent with secondary tuberculosis. PET/CT showed FDG-avid pulmonary lesions and bilateral vocal cord thickening with pericardial fat stranding consistent with glottitis (vocal cord SUVmax 6.78). Case 3: 60-year-old ex-smoker with 6 months of hoarseness of voice and stridor; CT revealed a left vocal cord nodule with local fat invasion, and PET showed an FDG-avid lesion (SUVmax 4.95) with multiple low FDG-avid cervical nodes. Laryngoscopy and biopsy confirmed moderately differentiated squamous cell carcinoma. Conclusions Understanding these variations in FDG uptake is essential, particularly for inexperienced PET/CT readers. This knowledge helps avoid misinterpretation and ensures accurate diagnosis and patient care.