Immunohistochemical demonstration of thyroglobulin in thyroid pathology

Thyroglobulin (Tg) was detected by the immunoperoxidase method in the following thyroid diseases: euthyroid goiter, Graves' disease, Hashimoto's thyroiditis, folliculo-papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma. Thyroglobulin was present in all benign lesions. The highest immunohistochemical staining reaction was found in Graves' disease. In euthyroid goiter, some colloid-distended macrofollicles did not show any Tg staining. A heterogeneous pattern of Tg staining was displayed especially by thyroid carcinomas. In most cases of papillary and follicular carcinomas Tg was detected in some neoplastic cells and sometimes in the colloid. There were differences in Tg content between different fields of the same tumor. In all anaplastic carcinomas a negative Tg staining was found. Vizualization of Tg in thyroid carcinomas is important for estimating the degree of differentiation and for indicating the thyroidal origin of metastases of adenocarcinomas.