Clinical presentation: A 61-year-old woman was referred for evaluation of elevated aTPO level detected on screening.

Palpation: No abnormality.

Laboratory tests: TSH 2.58 mIU/L, FT4 12.2 pM/L, aTPO 109 U/mL.

Ultrasound. The thyroid was echonormal, inhomogeneous and presented small hypoechogenic lesions. The echogenicity index was around 5%. There was a moderately hypoechogenic nodule in the central part of the right lobe. The nodule had cystic areas, halo sign and perinodular blood flow. There were echogenic figures within the nodule, some of them corresponded to connective tissue and back wall cystic figures but there were punctate echogenic foci (i.e. microcalcifications), as well.

Aspiration cytology resulted in benign follicular proliferation.

Suggestion. TSH determination in a year, ultrasound in 3 years.

Comment. The lesion is very likely a nodule in pathological sense.