Clinical data: a 68-year-old man was referred for evaluation of a suddenly developed thyroid tumor. The goiter had evolved over 2 months. 

Palpation: both thyroids were extremely enlarged and were hard and painless.

Functional state: subclinical hypothyroidism (TSH 8.38 mIU/L, FT4 13.1 pM/L).

Ultrasonography: the thyroid was composed of hypoechogenic nodules. Only a small rim of normal thyroid parenchyma remained in the lateral part of the lobes. 

Cytological picture: a few pleomorphic dispersed cells were found on the smears. Cytological diagnosis: anaplastic carcinoma.

Histopathology: anaplastic cancer.