Clinical presentation: a 31-year-old woman was evaluated because of sterility and a subclinical hypothyroidism was diagnosed.

Palpation: both thyroids were moderately firm and a small, more firm nodule was palpated in the left lobe.

Functional state: subclinical hypothyroidism (TSH-level 7.01 mIU/L, FT4 14.2 pM/L).

Ultrasonography: the thyroids were moderately hypoechogenic. There was a lesion with similar echo structure in the central part of the left lobe. The nodule displayed a halo sign and both perinodular and intranodular blood flow.

Cytological diagnosis: Hashimoto's thyroiditis. Suspicion of Hürthle-cell tumor.

Histopathology: Hashimoto's thyroiditis and oxyphilic variant of papillary carcinoma based on the nodule in the left thyroid.