Minute carcinoma of the thyroid and its development to advanced carcinoma

The relationship between the size of carcinomas and their histological characteristics such as encapsulation and sclerosis was studied using 157 cases of thyroid minute carcinomas with diameters less than 10 mm. When the diameter of the tumor was less than 1 mm, encapsulated carcinomas were not found, but they were presented in a group with a larger diameter. Sclerosing carcinomas were more frequently distributed in the group with a diameter less than 5 mm. With increasing tumor size, the carcinomas were reduced markedly in number and only two cases of sclerosing carcinoma were observed with a diameter more than 8 mm. It was concluded that thyroid minute carcinomas arise as nonencapsulated carcinoma, either sclerosing or non-sclerosing, followed by encapsulation at a later time and that some of the non-sclerosing carcinomas become apparent clinically, whereas most of the sclerosing carcinomas remain clinically silent throughout the entire life of the host.