Incidental Thyroid Uptake on 18 F-FES PET/CT Revealing Papillary Thyroid Carcinoma.
Pinar Akkus Gunduz, Mahsun Cidemal, Asena Gokcay Canpolat et al.
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Case in brief
A 70-year-old woman with endometrial carcinoma underwent 18F-FDG and 18F-FES PET/CT for pretreatment evaluation. Both scans showed focal uptake in a left inferior thyroid nodule. Ultrasound classified it as TI-RADS 3, while fine-needle aspiration showed atypia of undetermined significance. After total thyroidectomy, histopathology identified a 20-mm noninvasive encapsulated classic papillary thyroid carcinoma. ER immunohistochemistry was unavailable, so the relationship between FES uptake and ER expression could not be assessed. She subsequently received 100 mCi of radioactive iodine.
What made this case unusual
The thyroid carcinoma was incidentally detected as focal uptake on both FDG and FES PET/CT; the unavailable ER immunohistochemistry left the significance of FES uptake unresolved.
Diagnostic / clinical pearl
Focal thyroid uptake on PET/CT warrants evaluation even when ultrasound and cytology are not definitive; in this case, histopathology established papillary thyroid carcinoma.