Chief cell hyperplasia accounts for ˜15% of patients with primary hyperparathyroidism.1,4 Significantly, 25% to 35% of individuals with chief cell hyperplasia have a history of familial hyperparathyroidism or multiple endocrine neoplasia1,4 (see Chap. 188).

In chief cell hyperplasia, all four glands are enlarged.4 If the glands are of unequal size, it is usually the lower glands that are larger.5 Occasionally, the finding of one gland that is much larger than the others may erroneously suggest an adenoma.