Abstract
We herein report five cases of squamous cell carcinoma of the thyroid gland whose pathogenesis and clinical characteristics were examined in our department between 1979 and 2010. Direct transition from papillary carcinoma was responsible for the pathogenesis of the disease in 4 patients, and an ectopic squamous epithelium or remaining fetal tissue was suspected in 1 patient. Squamous cell carcinoma of the thyroid gland shows a rapid progression and a poor prognosis, and it is similar to anaplastic carcinoma. Although the local control of the cases completely cured by surgery is good, the possibility for subsequent occurrence of multiple cancers needs attention. In addition, it is necessary to always consider the possibility of direct invasion and metastases from multiple organs and to carry out a thorough examination of the entire body.
