Functioning oxyphil cell adenoma of the parathyroid gland: a clinicopathologic study of ten patients with hyperparathyroidism.

Adenomas of the parathyroid gland, the majority of which are of the solitary chief cell type, are the most frequent cause of primary hyperparathyroidism. Parathyroid adenomas composed predominantly or exclusively of oxyphil cells are rare and were previously considered nonfunctioning. Among 160 consecutive patients with primary hyperparathyroidism who were explored surgically, ten (6.25 per cent) had adenomas of the oxyphil cell variety. The eight women and two men in this series ranged in age from 28 to 82 years (average, 58 years). The tumors weighed from 0.2 to 4.0 g (average, 1.2 g). Nine of the adenomas were located in the left neck, while the remaining tumor was in the right neck. Histologically, the tumors were composed almost exclusively of transitional and typical oxyphil cells. A residual "capsular" parathyroid composed of chief cells was identified in each case. Electron microscopy, phosphotungstic acid-hematoxylin staining, and the immunoperoxidase technique for cytochrome c oxidase showed the presence of numerous mitochondria in oxyphil cells. All patients had normal serum calcium levels four months to four years (average, 23 months) after removal of the neoplasms.