18 F-FDG PET/CT in Cystic Papillary Thyroid Carcinoma.

A 52-year-old woman was evaluated for the appearance of a neck lump and dysphonia. Neck ultrasonography showed a large cystic nodule in the right thyroid lobe, confirmed by fine-needle aspiration cytology. Thyroid function and calcitonin were normal. 18 F-FDG PET/TC showed moderate tracer uptake by the outer ring of the large hypodense formation. Right hemithyroidectomy was performed; since intraoperative histology showed an intracystic and invasive papillary thyroid carcinoma, a completion thyroidectomy was done. Definitive histopathology confirmed the intraoperative findings. 18 F-FDG PET/CT may be a useful imaging procedure in evaluating patients with cystic thyroid nodules whenever clinical/ultrasonographic features are suspicious for malignancy.