Clinical presentation: A 38-year-old man was referred for ethanol sclerotherapy. The patient noticed a nodule 2 months ago. On aspiration cytology 11 mL fluid was removed, cytology resulted in non-diagnostic puncture. The patient noticed that the cyst had refilled within 2 weeks.

Palpation: The right lobe had an elastic nodule.

Result of blood test: TSH 0.90 mIU/L.

Ultrasonography. The thyroid was echonormal. There was a large cystic nodule in the right lobe. The type of the cyst could not be determined. The nodule contained numerous, ragged echonormal tissue fragments having echogenic granules. The left lobe had a small, insignificant lesion.

11 mL brown fluid was aspirated. Cytology resulted in non-diagnostic report.

Suggestion: Considering the unusual ultrasound presentation, the possibility of a papillary carcinoma was raised and surgery was advised.

Histopathology disclosed papillary carcinoma.

Comment. There were two suspicious findings. First, the overall presentation of the nodule was very unusual. Second, the ratio of echogenic granules was significantly higher in the solid parts of the nodule compared with that in the cystic part of the lesion.