The cause of primary hyperparathyroidism is unknown. Since this condition is not one pathological entity, but involves at least two and possibly more conditions, the heterogeneity of pathology probably means heterogeneity of causes. Recent data suggest that in most patients with parathyroid adenomas, there is a monoclonal disorder that arises from an abnormality within a single cell. However, four-gland hyperplasia may be a polyclonal disorder caused by an external stimulus to parathyroid cell growth, as well as PTH synthesis and secretion.
