All are true about hyperparathyroidism except?

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.