Parathyroid Adenoma and Its Differential Diagnoses

Abstract

This chapter discusses the key considerations in the differential diagnosis of parathyroid lesions by demonstrating a classical example of a parathyroid adenoma. Salient cytomorphologic features are shown in tandem with relevant clinical investigations, highlighting the importance of robust clinicopathologic correlation in differentiating parathyroid from thyroid lesions. Both cytoarchitectural and cytomorphological features are presented, with a discussion on the morphologic overlaps and differences between parathyroid and thyroid lesions. Key differential diagnoses are discussed, including follicular cell-derived thyroid nodules and medullary carcinoma. In addition to morphological features, the application of discriminatory biochemical and immunocytochemical ancillary tests is also discussed. Lastly, examples of other parathyroid lesions such as parathyroid hyperplasia and parathyroid carcinoma, are also illustrated.