<prompt> All are true about hyperparathyroidism except?Solitary adenomaMalignantThyroid malignancyParathyroid hyperplasia  <response>: 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. 