Anaplastic transformation of medullary thyroid cancer.

The paper presents a detailed microscopic study of a case of medullary thyroid carcinoma with the loss of amyloid production and of argyrophilic cellular granules combined with the prevalence of giant multinucleated cells in a part of the primary tumor and namely in metastatic deposits. These changes are believed to give evidence of anaplastic dedifferentiation. Similar cases to that reported are reviewed with the conclusion that not only differentiated thyroid cancers but medullary thyroid cancers as well are capable of anaplastic transformation. However rare the medullary thyroid cancers are, they should be diagnosed and radically treated so as to prevent their fatal anaplastic transformation.