Squamous cell carcinoma with cyst of the thyroid.

Two cases of primary squamous cell carcinoma associated with a thyroid cyst in the thyroid are described. The majority of squamous cell carcinomas reported so far have had some degree of co-existing adenocarcinoma, while the cases presented in this report had no glandular component at all. The histogenesis of squamous cell carcinoma is not clear, but at present, it is believed that most cases arise from the follicular epithelium. In our cases, in spite of an intensive examination of serially sectioned specimens, no areas of adenocarcinoma, squamous metaplasia from the follicular epithelium, or congenital squamous remnants could be found.