The case of a 76-year-old white woman with squamous cell carcinoma of
the thyroid gland arising in a background of Hashimoto's thyroiditis i
s presented. Squamous cell carcinoma of the thyroid gland is a very ra
re and aggressive tumor, and only a few cases are reported as arising
in Hashimoto's thyroiditis. Although Hashimoto's thyroiditis alone doe
s not necessarily predispose patients to malignancy, the finding of a
prominent nodule in such a patient should suggest the possibility of m
alignancy, and an aggressive search and treatment regimen, including s
urgical intervention, should be pursued.