Immunohistochemical localization of thyroglobulin (Tg), thyroxine (T4), and triiodothyronine (T3) in thyroid diseases.

Thyroglobulin (Tg), thyroxine (T4), and triiodothyronine (T3) were detected by the immunoperoxidase method in 51 cases of the following thyroid diseases: euthyroid goiter, Basedow's disease, Hashimoto's thyroiditis, folliculo-papillary carcinoma, follicular carcinoma, anaplastic carcinoma, and medullary carcinoma. Tg, T3, and T4 are present in most of the examined disorders, excepting anaplastic and medullary carcinoma. The pattern of Tg, T3, and T4 distribution between the cases of a benign lesion is rather similar; Tg and T4 are localized both in the epithelium and the colloid; T3 is disposed especially in the follicular cells. The pattern of Tg, T3, and T4 distribution in differentiated carcinomas is more heterogeneous. In half of the cases, T3 distribution resembled that of Tg. In 2 cases, a predominance of T4 was noted. In the other specimens, T3 and T4 showed a weak or a negative immunostaining.