Clinical presentation: A 51-year-old woman came to a follow-up visit. We have already met the patient four times in the past 10 years. At the first two occasions a diffusely enlarged echonormal thyroid was found containing three moderately hypoechogenic nodules. Four years before the present examination, the thyroid became inhomogeneous and presented several discrete areas and we described no nodules. She had no complaints and never get any thyroid medications.

Palpation: Both lobes were enlarged, no nodules could be palpated.

Hormonal investigation: euthyroidism (TSH 0.45 mIU/L, FT4 11,1 pM/L, aTPO 0.5 U/mL).

Ultrasonography. The thyroid was minimally-moderately hypoechogenic and showed marked proliferation of connective tissue. There were many discrete more and less hypoechogenic areas. None of them fit to a nodule in pathological sense.

Diagnosis. Diffuse goiter. Suspicion of Hashimoto's thyroiditis.

Suggestion: follow-up examination in two years.

Comment. Unfortunately, we did not record the ultrasound images previously. Nevertheless, the change in the echo pattern, i.e. the process on which the entire thyroid turns form echonormal to hypoechogenic, is in accordance with lymphocytic thyroiditis. You can find many examples on the website in which a nodule diagnosed on ultrasound proves to be only a more active or the only one focus of Hashimoto's thyroiditis. It seems to be evident that in significant number of these cases the thyroiditis spreads over the entire thyroid over years or decades.