Clinical presentation: A 53-year-old woman was referred for an evaluation of a suspected hypothyroidism. She gained 15 kg in weight. She noticed a lump in the right thyroid a year earlier which caused no complaints.

Palpation: a very firm nodule in the left lobe.

Hormonal examination indicated euthyroidism with TSH 3.14 mIU/L.

Ultrasonography. There was a solitary hypoechogenic nodule in the right thyroid. The lesion showed halo sign and perinodular blood flow.

Cytology resulted in follicular tumor with greater than average risk of malignancy.

Histopathology disclosed minimally invasive follicular cancer.

Comment. It is worth comparing the first five cytological images with the last five pictures. The former suggests a typical follicular proliferation while the latter does an atypical follicular tumor. The images came from different parts of the same smear.