Clinical presentation: A 38-year-old woman was referred for evaluation of thyroid disorder. She has been treated for autoimmune thyroiditis for more than 8 years. Levothyroxine therapy was initiated 7 years ago despite a normal TSH level. She noticed a continuous increase in the size of the thyroid which caused compression sign in supine position.

Palpation: The thyroid was enlarged and nodular on palpation.

Functional state: euthyroidism on daily 75 microgram levothyroxine (TSH 0.51 mIU/L, aTPO 0.5 U/mL).

Ultrasonography. Both lobes were composed of multiple nodules of different echogenicities including cystic ones and a large hyperechogenic lesion in the lower part of the right lobe. Except for a moderately hypoechogenic nodule in the dorsal part of the left lobe, the lesions had no oncological significance. The extranodular part was echonormal.

Cytology was performed form the moderately hypoechogenic nodule in the dorsal part of the left lobe and resulted in benign lesion.

A total thyroidectomy was performed. Histopathology disclosed benign hyperplastic nodules. There was neither focal nor diffuse thyroiditis.