Adjacent to this parathyroid adenoma is a rim of normal parathyroid tissue (with a pink oxyphil cell nodule) at the upper right, and a small benign parathyroid cyst (an incidental finding) is at the upper left. Patients with this form of primary hyperparathyroidism are usually picked up with routine chemistry panels in which a high serum calcium is noted. A parathormone (PTH) assay reveals a high normal to elevated level of PTH.