Incidental thyroid cancer detected by FDG-PET/CT

1515 Objectives Focal increased FDG uptake in thyroid cancer found incidentally in patients undergoing FDG-PET/CT is not rare . The aim of this study was to investigate the prevalence of incidentally found thyroid lesions in patients undergoing FDG-PET/CT . Methods 2575 FDG-PET/CT study was performed for evaluation of suspected or known cancer or cancer screening without any history of thyroid cancer between January 2014 and December 2015. FDG-PET/CT findings including SUV max and focallly increased pattern of FDG uptake, and medical records including US findings, fine needle aspiration biopsies and histopathology reports re were reviewed retrospectively. Results Eighty one patients (3,14%) were identified to have a focal FDG uptake on FDG-PET/CT. Whereas 31 patients with focal FDG uptake had undergone further evaluation. The cancer risk of incidentally found thyroid cancer with focally increased FDG uptake on FDG-PET/CT was 25,8% (8/31) among the patients who had and ultrasound and FNA . There was a significant difference in the SUVmax between the benign and malignant nodules (5,70 ± 2,77 vs. 10,8 ± 9,35 ; P < 0.001). Also there were two patients with metastatic involvement of thyroid gland which had also a focally increased uptake Conclusions The results of this study suggest that incidentally found thyroid lesions by FDG-PET/CT, especially a focal FDG uptake and a high SUV, have a high risk of thyroid malignancy. Also one has to consider the risk of a metastatic lesion when reporting a focal uptake in thyroid gland. In our study the rate of patients who had undergone an US and FNA is low . But clinicians must be aware of a synchron malignancy and /or thyroid metastasis where it may change clinical consideration