Clinical data: a 24-year-old woman requested an evaluation of thyroid dysfunction detected by chance on routine laboratory investigation for two weeks. The GP administered 20 mg methimazole. She had no complaints suggesting hyperthyroidism.

Palpation: a moderately firm nodule in the left lobe.

Functional state: hypothyroidism on daily 20 mg methimazole: TSH 8.72 mIU/l, FT4 8.51 pM/L, TSAb 0 U/L, anti-TPO 108 U/mL.

The lesion in question was located in the left lobe.