A Patient Presenting with an Incidentally Found Hypermetabolic Thyroid Nodule on FDG-PET/CT

The prevalence of thyroid lesions on FDG-PET was reported as 4%, and the malignancy rate in these nodules was found to be 14–50%. We reported a case of thyroid incidentaloma, detected during follow-up of known primary malignancy. Thyroid nodule was detected in FDG PET/CT of a 68-year-old woman with known breast cancer during follow-up. Because of suspicious USG findings and high SUVmax value, fine needle aspiration biopsy (FNAB) was performed and the result came out as suspicious in terms of papillary carcinoma oncocytic variant (Bethesda Category V). If the thyroid nodule is detected with FDG uptake, the cytological examination is necessary to differentiate benign nodule from malignant ones and figure out whether it is a thyroid metastasis from primary cancer or not.