Differential Diagnosis of Thyroid Nodules via Real-Time PET/Ultrasound (US) Fusion in a Case of Co-existing Medullary Thyroid Cancer and Adenoma

A 52-year-old woman presented with apparent carcinoid syndrome. Gallium 68 (Ga)-DOTATOC positron emission tomography (PET)/computed tomography (CT) found a 2.5-cm somatostatin receptor (SR)positive nodule in the left thyroid lobe. Basal serum calcitonin was 5184 ng/L, TSH was 0.63 mU/L, and free T4 was 16.98 pmol/L, so medullary thyroid cancer was suspected. Ultrasonography (Figure 1, A and B), F-fluorodeoxyglucose (FDG) PET/CT, and iodine 124...