Clinical and experimental advances in sporadic primary hyperparathyroidism

Primary hyperparathyroidism (HPT) has shown prevalence of up to 3% among elderly women in Nordic health screening surveys, and is increasingly diagnosed in patients with diffuse neuromuscular or psychiatric symptoms. Primary HPT, even with mild hypercalcemia, is associated with increased mortality risk, mainly from cardiovascular disease. Despite the efficacy of new methods, reliable histopathologic distinction between adenomatous and hyperplastic parathyroid disease may still be difficult, and indeed circumstantial evidence suggests that adenoma and chief cell hyperplasia are not always distinctly separate pathophysiologic entities. Irrespective of symptoms, the hyperplasia is associated mainly with mild to moderate hypercalcemia, and may thus constitute an early form of HPT. A more liberal attitude to surgery in primary HPT would increasingly extend treatment to less clear-cut cases. The demonstration by monoclonal antiparathyroid antibodies of a specialized calcium receptor mechanism on the surface of parathyroid cells and its reduced expression in pathologic parathyroid tissue seems to explain defective parathyroid cell function and ensuing hypercalcemia in HPT. These antibodies appear to offer new prospects in parathyroid histopathology and research.