Clinical presentation: A 62-year-old woman requested a second opinion. She has noticed a lump in the right side of the neck for three months. On evaluation a moderate degree of hyperthyroidism was detected. The nodule did not take up radioiodine. TSAb and anti-TPO resulted in normal level. Cytology was not diagnostic, and surgery was advised.

Palpation: The right lobe was firm and nodular.

Functional state: subclinical hyperthyroidism on daily 15 mg methimazole: TSH 0.13 mIU/L, FT4 11.6 pM/L, FT3 4.07 pM/L.

Ultrasonography. A large hypoechogenic nodule occupied almost the entire right lobe. The nodule presented an incomplete halo and signs of perinodular blood flow. The left thyroid was moderately hypoechogenic and inhomogeneous and contained several relatively small nodules with different echogenicities in the range of 5-15 mm.

On all three attempts of aspiration cytology bloody material was gained and there were no thyroid cells on the smears.

Surgery was advised.

Histopathology disclosed papillary carcinoma corresponding to the nodule in the right lobe. More than 90% of the lesion was necrotized and a focus of papillary carcinoma with a maximal diameter of 15 mm was found on the edge of the nodule. The remaining nodules proved to be hyperplastic.

Comment. The borders of the nodule were obscure, and there were two reasons for this in different parts of the lesion: on the one hand, the probe could not be completely fitted to the patient's neck, and on the other hand, the focus was not properly adjusted.