Clinical data: a 35-year-old pregnant woman was referred for an evaluation of hypothyroidism detected on screening.

Palpation: the thyroids were firm, no nodule could be palpated.

Functional state: subclinical hypothyroidism (TSH-level 6.17 mIU/L).

Ultrasonography: both thyroids were moderately hypoechogenic. There were multiple inhomogeneous lesions in the left lobe.

Cytology: two different cell populations were found on the smears. The first corresponded to colloid goiter with lymphocytic thyroiditis (first row of cytological pictures). The other population was suspicious for papillary cancer (cytological pictures 6-11).

We administered levo-tiroxine. The patient was regularly followed-up hormonally and by ultrasound until the cessation of lactation. Thereafter she was operated.

Histopathology: multifocal papillary cancer in the left lobe. Hashimoto's thyroiditis.

Comment: considering the slow growing nature of papillary cancer, pregnant patients generally do not have to be operated during their pregnancy and lactation.