Clinical data: A 53-year-old woman was referred for evaluation of nodular goiter detected on examination of cervical disc herniation.

Palpation: a moderately firm nodule in the right lobe.

Laboratory test: TSH 2.71 mIU/L, FT4 12.3 pM/L, aTPO 150 U/mL.

Ultrasonography. The thyroid was echonormal. There was a moderately hypoechoic nodule in the right lobe. The nodule has halo and presents with a combined perinodular and intranodular blood flow. The latter was irregularly increased.

Cytology resulted in medullary cancer.

Serum calcitonin was measured which resulted in > 585 pM/L.

Histopathology disclosed medullary cancer.

Comments.

1. The presentation of the nodule is not very suspicious. Halo sign is a rare finding in medullary cancers.

2. The classification of the nodule depends on the judgement of nodule borders. If it is regarded as irregular, then the lesion is an EU-TIRADS 5 one. However, if we judge the borders as non-lobulated, then the lesion is an EU-TIRADS 4 nodule. According to the EU-TIRADS, FNA is indicated in both cases because the largest diameter of the nodule exceeds 15 mm.