HRPT2 in Parathyroid Cancer: A Piece of the Puzzle

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the general population. The disease has an incidence as high as 1 in 1000 individuals and occurs more commonly in women than in men (3:1). In approximately 80% of cases of PHPT, a single benign adenoma is the cause of abnormal parathyroid function. In 15–20% of cases, PHPT is due to hyperplasia of all four parathyroid glands. Rarely, multiple adenomas can be seen. In less than 1% of cases, the most scarce and deadly presentation of PHPT occurs, namely that of parathyroid carcinoma (1). The clinical presentation of benign PHPT has undergone a sea change over the past 30 years. The disease used to be a symptomatic disorder in which the hallmarks were kidney stones and the classical skeletal abnormality osteitis fibrosa cystica (2). With the advent of the multichannel autoanalyzer in the early 1970s, the typical presentation of PHPT evolved from that of a symptomatic disorder to one without clear symptoms in the vast majority of patients. Most symptomatic patients today have biochemically mild disease and nephrolithiasis.