Immunohistochemical staining in thyroid carcinoma: has it become a standard?

Abstract

This paper describes results of immunohistochemical studies, used to diagnose primary and metastatic thyroid tumours. We discuss differential diagnosis of medullary thyroid carcinoma and c-cell hyperplasia in patients with RET protooncogene mutation, who had undergone prophylactic thyroidectomy. In particular, we focus on the possible immunohistochemical differentiation of follicular thyroid tumours. We discuss technical issues encountered in applying immunohistochemical methods as well as the commonest errors in the inter-pretation of results. In conclusion, we indicate areas of thyroid pathology where immunohistochemical staining appears absolutely necessary, and others where such methods can merely assist in reaching final diagnostic decision.