Functioning Oxyphil Cell Adenoma of the Parathyroid Gland: Evidence for Parathyroid Secretory Activity of Oxyphil Cells

There has been no conclusive proof that oxyphil cells are capable of secreting parathyroid hormone. Likewise there has been no convincing evidence that oxyphil adenomas are associated with excess hormone production. A 70-yr-old patient presented with hypercalcemia, hypophosphatemia and subperiosteal bone resorption of her phalanges. Selective venous sampling of the neck veins showed elevated levels of parathyroid hormone in the right jugular vein as measured by radioimmunoassay. Surgical exploration of the neck revealed a parathyroid adenoma on the right side of the neck which consisted exclusively of oxyphil cells by light and electron microscopy. Electron microscopy of the tumor cells showed a striking abundance of mitochondria, numerous secretory granules, well-developed Golgi apparatus and rough surfaced endoplasmic reticulum, suggesting increased hormone secretory activity. Our findings indicate that pure oxyphil adenomas can be associated with hyperparathyroidism and that oxyphil cells are capable of secreting parathyroid hormone.