[Collision carcinoma of the thyroid gland in Hashimoto's thyroiditis. Spinocellular carcinoma, arising from a cyst of the thyroglossal duct and a follicular carcinoma with an anaplastic turn].

A collision carcinoma of the thyroid was revealed in a surgically removed thyroid affected with Hashimoto's thyroiditis. A follicular carcinoma composed of rather uniform and spherical cells. The anaplastic carcinoma appeared to collide with structures of a noncornifying squamous cell carcinoma supposed to originate in the isthmic area from a ductus thyreoglossus cyst.