Histology of the Parathyroid Glands

Abstract

An illustrated review of the histology of the parathyroid glands (PTGs) is provided in this chapter. Histologically, the PTG is formed of a small package of parenchyma, dotted with adipocytes (fat cells) and entwined with a complex vascular network and lined with a capsule (stroma). This capsule also separates the PTG from the thyroid gland. Trabeculae (connective tissue) extend inward from the capsule to partially outline irregular lobes and lobules of the PTG. Within the PTGs there are two main glandular components: parenchymal cells and fat cells. Parenchymal cells are seen to be made up of two main cell types: the “chief cells” (most abundant) and “oxyphilic cells” (fewer in number). Other parenchymal cells are “water-clear cells” with unknown recognized function, as they are fundamentally inactive and “fat cells.” This chapter provides also details about the immunohistochemical characteristics and neuroendocrine markers of the PTGs as well as their electron microscopic features.