All are true about hyperparathyroidism except?: (A) Solitary adenoma, (B) Malignant, (C) Thyroid malignancy, (D) Parathyroid hyperplasia
Answer is C. Hyperparathyroidism is usually due to a solitary adenoma. It can also be due to MEN Type 1 which accounts for about 90% of parathyroid cancers, which do not include thyroid malignancies in the group of the multiple endocrine neoplasms. Parathyroid hyperplasia can also lead to hyperparathyroidism.