Most common cause of hyperparathyroidism: March 2009: (A) Carcinoma, (B) Hyperplasia, (C) Adenoma, (D) Familial isolated hyperparathyroidism
Answer is C. Ans. C: Adenoma Hyperparathyroidism causes hypercalcemia through the excessive secretion of parathyroid hormone, usually by an adenoma (benign tumors) of the parathyroid glands (nearly 80%). Chief cell parathyroid hyperplasia accounts for nearly 15% cases.