Clinical data: A 61-year-old woman came to a routine follow-up. She has been diagnosed with Hashimoto's thyroiditis for 13 years. So far, no medication has been required for this.

Palpation: no abnormality.

Laboratory tests: TSH 2.74 mIU/L. The aTPO exceeded 1000 U/ml four years ago.

Ultrasonography. The thyroid was moderately hypoechoic and inhomogeneous and had multiple discrete lesions. There was a cystic lesion in the dorsal part of the left lobe.

1.5 mL light colored fluid was aspirated. There were no cells on the smear.

Additional tests: serum-parathormone 17.4 pg/mL (normal value 12-88), parathormone content of the aspirated fluid 1622 pg/mL.

Suggestion: TSH in a year, ultrasound in three years.