Clinical presentation: a 34-year-old woman was referred for an evaluation because of weight gain.

Functional state: subclinical hypothyroidism (TSH 8.96 mIU/L, FT4 10.1 pM/L).

Ultrasonography: several hypoechogenic circumscribed lesions within both lobes. The echogenicity index was around 30%.

Cytological report: benign Hashimoto's thyroiditis.

We prescribed daily 50 microgram levothyroxine.