Pathogenesis of Non-Toxic Goitre

Abstract

In clinical terms goitre is a thyroid enlargement above the gender- and age specific reference range and may present with euthyroid, hyperthyroid, or hypothyroid function. On morphological grounds, goitre may be diffuse or nodular. Histologically, thyroid nodules are distinguished by morphological criteria according to the World Health Organization (WHO) classification. On functional grounds, nodules are classified as either ‘cold’, ‘normal’, or ‘hot’ depending whether they show decreased, normal, or increased uptake of radioactive nuclides such as technetium on scintiscan. In contrast to solitary nodular thyroid disease, which has a more uniform clinical, pathological, and molecular picture, multinodular goitre (MNG) usually comprises a mixed group of nodular entities. The aetiology of non-toxic goitre includes extrinsic factors like dietary iodine and intrinsic factors like age, gender, or genetic disposition. This chapter discusses the interplay of the aforementioned aspects in the pathogenesis of benign non-toxic goitre.