Clinical data: A 18-year-old woman was referred for evaluation of a suddenly developed thyroid nodule. 4 mL cystic fluid was aspirated. The cytological report was not diagnostic. The nodule refilled 2 weeks after the previous examination.

Palpation: an elastic nodule in the right lobe.

Functional state: euthyroidism (TSH 1.09 mIU/L).

Ultrasonography: The right lobe was echonormal and had a mixed cystic-echonormal nodule. The solid part showed increased vascularity.

Cytological diagnosis: suspicion of papillary cancer.

Histopathology: papillary cancer.