Parathyroid Adenomas:
The most common cause of Primary Hyperparathyroidism.
Gross Appearance – weight 0.5 to 5.0 gm; is a well-circumscribed, soft, tan to reddish-brown nodule;
•Microscopically, parathyroid adenomas are mostly composed of fairly uniform, polygonal chief cells with small, centrally placed nuclei.
•Mitotic figures are rare, but frequent bizarre and pleomorphic nuclei even within adenomas (so-called endocrine atypia) – this is not a criterion for malignancy!
