Clinical presentation: A 34-year-old woman was referred for a screening because her mother had hypothyroidism.

Palpation. No abnormality.

Laboratory test: TSH 3.22 mIU/L, aTPO 9 U/mL.

Ultrasonography. The thyroid was minimally hypoechogenic and presented more hypoechogenic areas. There were no nodules of pathological sense.

Diagnosis: Hashimoto's thyroiditis.

Suggestion: TSH determination in 6 months, in the event of pregnancy at once.

Comment. In mild forms of Hashimoto's thyroiditis, the sensitivity of ultrasound is clearly superior to aTPO determination in detecting autoimmune thyroiditis.