Clinical data: A 72-year-old woman was referred for an evaluation of a rapidly increasing nodular goiter which had a 2-month history.

Palpation: a very hard large tumor in the region of the right lobe.

Ultrasonography. A large hypoechogenic, inhomogeneous tumor occupied almost the entire right lobe. The left lobe was intact.

Functional state: euthyroidism (TSH 1.15 mIU/L).

Cytology resulted in anaplastic cancer.

Histopathology disclosed anaplastic cancer.