What are etiologies of hyperPTH?

-In 85% of cases=single adenoma -In 15% of cases=multiple glands are involved(multiple adenomas or hyperplasia) -Rarely=parathyroid carcinoma -The etiology of adenomas or hyperplasia=unknown -Familial cases can occur as either part of *the multiple endocrine neoplasia syndromes (MEN 1 or MEN 2a), hyperparathyroid-jaw tumor (HPT-JT) syndrome *familial isolated hyperparathyroidism (FIHPT)