Clinical presentation: A 48-year-old man was referred for evaluation of a thyroid nodule discovered by chance.

Palpation: no abnormality.

Functional state: euthyroidism with TSH 1.42 mIU/L.

Ultrasonography. The thyroid was echonormal. There was a cystic nodule in the lower part of the left lobe. The lesion contained several typical comet-tail artifacts.

On aspiration, thick gelatinous material was gained. Cytology resulted in benign cystic-colloid goiter.

Comment. It is worth analysing the typical presentation of colloid crystals and that of the posterior acoustic enhancement.