Anaplastic spindle-cell and giant-cell tumors of the thyroid gland

Fifty-three cases of anaplastic spindle-cell and giant-cell tumors of the thyroid gland were found in the files of the University of Michigan Medical Center in a 37-year period (1932-1969). Of these, 42 were found with other well-differentiated thyroid carcinomas: papillary, follicular, Hürthle cell, clear cell, and medullary carcinomas. Data from this report and the recent literature support the conclusion that anaplastic tumors of the thyroid gland probably arise in preexisting well-differentiated thyroid carcinomas. The grim prognosis for anaplastic carcinomas of the thyroid gland is reemphasized in this study; 49 of the 53 patients died within the first year after a histologic diagnosis was established.