Primary hyperparathyroidism (pHPT) is a common endocrine disorder that predominantly affects postmenopausal women. It is mostly caused by solitary tumours within the parathyroid glands. Although the pathophysiology of pHPT is still incompletely understood, recent studies provide new clues on the development and cellular growth of tumours within the parathyroids associated with hypersecretion of parathyroid hormone and hypercalcaemia. The natural course of pHPT is rather benign. Nowadays, it has become an oligo- or asymptomatic disease often only detected by routine blood tests. These facts raise the question whether to perform parathyroidectomy on oligo- and asymptomatic patients with pHPT or whether it is possible to monitor these patients without surgery. The aim of this article is to review the literature as regards (i) the pathophysiological mechanisms that underlie parathyroid neoplasia and (ii) the defective calcium-sensing in patients with pHPT (iii) environmental and/or genetic risk factors that predispose to or promote parathyroid neoplasia, as well as (iv) alternative approaches to treat oligo- and asymptomatic patients with pHPT medically.