Chief cell and clear cell parathyroid adenoma do not influence clinical and biochemical expression of the sporadic primary hyperparathyroidism

Abstract

Primary hyperparathyroidism (PHPT) is a common endocrine disorder and the most common cause of PHPT is parathyroid adenoma [1]. The normal parathyroid gland is composed of three types of cells—chief (50–60 %), clear (30–40 %), and oxyphil cells (\5 %) [2]. The chief cells have slightly eosinophilic cytoplasm and contain few mitochondria and these cells mainly secrete parathyroid hormone (PTH) [2]. Clear cells, which contain excessive cytoplasmic glycogen, are formed from chief cells while oxyphil cells have an intensely eosinophilic cytoplasm enriched with numerous and tightly packed mitochondria [3]. The function of clear and oxyphil cells is still not clear [2, 3]. Though the exact percentage of various cell types of adenoma is not known, chief cell adenoma is documented to be the most common cause of PHPT [4]. Since the chief cells are the principle cells secreting PTH, chief cell adenoma is expected to present with classical symptoms of PHPT. The clinical and biochemical presentation of clear cell adenoma is not known. There are few case reports of water clear cell adenoma presenting with classical symptoms of PHPT and these cells are positive for PTH immunostaining [5–8]. Furthermore, there is no study in the literature to compare the clinical and biochemical parameters of PHPT between chief cell and clear cell parathyroid adenoma. Considering these lacunae in literature, the present study was planned.