Clinical data: A 38-year-old woman was referred for aspiration cytology. She has been treated for hypothyroidism for six months.

Palpation: no abnormality.

Functional state: euthyroidism on daily 75 microgram levothyroxine (TSH 2.97 mIU/L).

Ultrasonography. The thyroid was minimally hypoechogenic. The left lobe contained a cystic lesion and two hypoechogenic nodules next to each other. These lesions presented microcalcifications and irregularly increased intranodular vascularization.

Cytology resulted in the suspicion of oxyphilic variant of papillary carcinoma.

A total thyroidectomy was performed. Histopathology disclosed Hashimoto's thyroiditis. The cystic lesion proved to be a hyperplastic nodule while corresponding to the nodules in the lower part of the left lobe, oxyphilic variant of papillary carcinoma was diagnosed.