Clinical presentation: A 44-year-old woman has been treated for Graves' disease for 4 years. She had a temporary elevation of FT4 level 6 weeks ago, which has spontaneously resolved. She came to routine follow-up examination.

Palpation: There was a firm nodule in the right lobe.

Functional state: subclinical hyperthyroidism with TSH 0.09 mIU/L, FT4 19.1 pM/L.

Ultrasonography. The thyroid was minimally hypoechogenic with normal vascularization. There was a hypoechogenic nodule in the ventral part of the right lobe. The nodule presented irregular, lobulated margins, microcalcifications and increased intranodular vascularization.

US-guided aspiration was performed from the nodule. Cytology resulted in papillary carcinoma.

Histopathology disclosed papillary carcinoma with extracapsular spread into the sternocleidomastoid muscle and Hashimoto's thyroiditis.

Comment.

1. The nodule presents lobulated margins and extrathyroidal spread.

2. The nodule should be regarded as an EU-TIRADS 5 lesion because of the presence of microcalcification and irregular borders.