Incidental FDG-Avid Focuses in Palatine Tonsils on PET/CT.

Abstract

The management of incidental findings of FDG-avid tonsils on PET/CT (IFT) is unclear. We aimed to explore the prevalence of malignancy in IFT, identify risk factors for malignancy, and calculate optimal cutoffs of maximum standardized uptake values (SUVmax ) to discriminate between benign and malignant lesions. All patients who were tonsillectomized at our institution because of IFT from October 2011 to December 2020 were included. Patients undergoing PET/CT due to suspected tonsillar disease or cancer of unknown primary were excluded. In total, 77 patients were included, of which 11 (14%) of them had IFT malignancy. Dysphagia (p=0.019) and alcohol abuse (p=0.035) were associated with malignancy. Absolute SUVmax cutoff (≥9: sensitivity 100%; specificity 53%) was superior to SUVmax side-to-side ratio (≥1.5: sensitivity 64%; specificity 70%) to discriminate between benign and malignant lesions. We recommend tonsillectomy for patients with IFT displaying SUVmax ≥ 9.0, ratio ≥ 1.5, or symptoms or findings suggesting malignancy. 3 Laryngoscope, 132:2370-2378, 2022.