Clinical data: A 72-year-old woman came to a follow-up visit. She has been treated for hypothyroidism for 21 years.

Palpation: The right lobe was enlarged and very firm and had uneven surface.

Laboratory tests: TSH 0.02 mIU/L, FT4 19.7 pM/L on daily 125 microgram levothyroxine.

Ultrasonography. The thyroid was echonormal and presented numerous hypoechogenic discrete areas. None of the met the criteria of a pathological nodule. The right lobe was substantially enlarged and spread dorsally. The lower pole of this lobe could be almost visualized on longitudinal scan which makes significant substernal spread unlikely. Compared with the previous examinations, the right lobe has not increased in size.

Suggestion: to decrease the dose of levothyroxine to daily 100 micrograms.