Thyroglobulin production by malignant thyroid tumors. An immunocytochemical and radioimmunoassay study.

Four hundred thirty surgical and biopsy specimens of malignant thyroid tumors of 323 patients were analyzed by histologic and immunocytochemical examination for their thyroglobulin (TG) content. Almost 95% of the differentiated thyroid carcinomas of follicular origin contained immunoreactive TG. The authors could not demonstrate TG in anaplastic carcinomas. Postoperative follow-up and serum TG determinations were available for 111 athyroid patients. Serum TG was elevated in five patients with metastatic or recurrent moderately differentiated follicular carcinoma, in two patients with metastasizing papillary, and in one patient with anaplastic carcinoma. Four patients had detectable serum TG levels without clinical and radiologic evidence of recurrence or metastases. In addition to conventional histologic examination, immunocytochemical demonstration of TG is a reliable and valuable aid in the diagnosis, classification, and determination of the grade of differentiation of malignant thyroid tumors. From this the pathologist can provide a pathologic basis for postoperative patient management.