Water-clear-cell hyperplasia mimicking parathyroid adenoma.

The case of a patient with primary hyperparathyroidism in whom water-clear-cell hyperplasia (WCCH) involved only the superior glands, and disproportionately so, is presented. In addition, unlike the cases of WCCH described previously, a rim of normal parathyroid tissue was observed at the periphery of each gland in this case. It is speculated that these findings are not necessarily peculiar, but may reflect an earlier stage of the disease. Such cases may mimic parathyroid adenoma, thereby leading to inadequate surgical therapy.