Clinical presentation: A 65-year-old hypothyroid woman was referred for follow-up examination of a nodular goiter. Aspiration cytology was benign five years ago. She has been treated for hypothyroidism for five years.

Palpation: a firm nodule in the right lobe.

Hormonal investigation: euthyroidism on daily 50 microgram levothyroxine (TSH 2.93 mIU/L). The aTPO was 1 U/mL at the time of the discovery of hypothyroidism.

Ultrasonography. Both lobes were composed of a large echonormal nodule surrounded with a thin hypoechogenic rim. The nodules displayed halo sign and perinodular blood flow. The dimensions of the nodule in the right lobe increased from 23x15x24 mm to 30x20x30 mm, from 2011 to 2016. The left nodule remained unchanged.

Aspiration cytology resulted in benign follicular proliferation.

Suggestion: daily 50 microgram levothyroxine. Repeat ultrasound and TSH in a year.

Comment. It is worth noticing that although the nodule in the right lobe is relatively large, the right lobe itself is only minimally increased, it means that the nodule replaces the normal parenchyma and is not added to a normal-sized thyroid. We should never forget that the indication of thyroid surgery should be based on the size of a lobe and not on the size of a benign nodule.