Functioning oxyphil cell adenoma in a patient with secondary hyperparathyroidism.

A 45-year-old Japanese woman who has been receiving haemodialysis for 13 years suffered from an ectopic calcifying nodule and deformity of the thorax. She was diagnosed as hyperparathyroidism secondary to chronic renal failure. Total parathyroidectomy was performed, and the excised parathyroid glands showed hyperplasia in four and an adenoma in the left upper gland. On the electron microscopic study, the adenoma was composed of oxyphil cells and transitional oxyphil cells, the latter predominating in number. It was revealed from immunohistochemical study that the oxyphil cells in adenoma were strongly stained for parathyroid hormone (PTH). Continuous stimuli to secrete PTH seemed to generate the functioning oxyphil cell adenoma with an ability of PTH production, as well as hyperplasia of parathyroid chief cells. It seems to be the first case of tertiary hyperparathyroidism caused by an oxyphil cell adenoma. Functions of oxyphil cells and transitional oxyphil cells are briefly discussed.