Primary parathyroid hyperplasia of water-clear cell type. Transformation of water-clear cells into chief cells.

An exceptional case of water-clear cell hyperplasia (WCCH) of the parathyroid glands is presented. Parathyroid tissue was excised at three operations during a period of twenty years before the patient eventually became normocalcemic. Microscopic evaluation of the parathyroids from the first operation showed typical WCCH-findings.