The Significance of Amyloid in Carcinoma of the Thyroid Gland

Abstract

This paper deals with the description of 2 examples of medullary carcinoma of the thyroid gland, with formation of amyloid in the tumors. Forty-five examples of other histologic types of thyroidal carcinoma failed to manifest fluorescent staining of amyloid. The "amyloid" is thought to be derived from thyroglobulin secreted by the carcinoma cells. The mechanism is probably related to the shift from neutral to acidic mucopolysaccharide moiety in the glycoprotein (thyroglobulin). The presence of "amyloid" in medullary carcinoma reflects, therefore, a relatively high degree of thyroidal function and differentiation; this may be related to the good prognosis associated with this tumor.