Clinical presentation: A 77-year-old woman presented with an increasing mass in the left thyroid lobe. Laryngology revealed palsy of the right recurrent nerve. She had dyspnea and difficulties in swallowing. The tumor evolved over 2 to 3 months.

Palpation: a very hard nodule in the right lobe.

Functional state: euthyroidism.

Ultrasonography. There was a hypoechogenic nodule occupying the right lobe and the isthmus. The nodule contained amorphous hyperechogenic foci and cystic degeneration which corresponded to necrosis. The dimensions of the nodule were 49x25x51 mm.

Cytological picture: There was no colloid in the background. There were naked, atypical, pleomorphic cells resembling lymphoblast on the smear. They occurred dissociated, no specific cell groups can be identified. Most of the cells presented severe degenerative changes. The cytological pattern highly resembled that of anaplastic cancer or a high grade malignant lymphoma.

Cytological diagnosis: malignant tumor. Suspicion of anaplastic cancer.

Histopathology disclosed medullary cancer.

Comments.

1. The tumor did not present typical cytological signs of a medullary cancer. The cellular details were difficult to judge because of degenerative changes.

2. Anaplastic cancer should be considered even on the clinical presentation.