Multinodular goitre: pitfalls in the interpretation of thyroid follicular nodular disease

Abstract

Thyroid follicular nodular disease (FND), formerly known as multinodular goitre is one of the commonest thyroid pathologies and can show variable clinical presentation and a variety of histopathologic features. The microscopic features of thyroid FND can sometimes mimic those of well-differentiated thyroid malignancies. It is important to recognise this range of appearances to avoid over diagnosis of neoplasia. Macroscopic examination of thyroid specimens and correlation with microscopic features can be helpful in interpreting nodules with atypical appearances. We describe the variety of histologic features which can be encountered in thyroid FND. We also describe how fibrosis and other changes secondary to haemorrhage and inflammation in thyroid FND can produce worrisome histologic appearances, in and around nodules which can be misinterpreted as invasive malignancy. This review aims to update on the histopathology of thyroid FND and to focus on pitfalls in microscopic interpretation.