Clinical presentation: A 16-year-old girl was referred for aspiration cytology. She was investigated because of fatigue.

Palpation: no abnormality.

Functional state: euthyroidism (TSH 1.91 mIU/L).

Ultrasonography. The thyroid was echonormal. There was a hypoechogenic lesion in the ventral part of the right lobe. The nodule showed irregular margins, taller-than-wide shape and microcalcifications. The lesion was avascular on Doppler method.

Cytology resulted in papillary carcinoma.

Histopathology disclosed a solitary focus of papillary microcarcinoma. The maximal diameter of the tumor was 7 mm.

Comment. The tumor presents ill-defined and lobulated margins.