Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders and the principal cause of hypercalcemia. The prevalence of PHPT is 1 to 4 per 1,000 in the general population. PHPT is usually diagnosed at an asymptomatic stage as mild hypercalcemia, generally discovered during routine biochemical screening. Classical clinical manifestations of PHPT are still observed mainly, although not only, in developing countries. Open questions still exist in the field of PHPT, including the optimal pharmacologic approaches to lowering fracture risk, the impact of PHPT on cognition and cardiovascular, gastrointestinal, and musculoskeletal systems, the need to standardise and improve the imaging algorithm for preoperative localization, and the appropriate follow-up for non-surgically treated patients.

The aim of this special issue is to deeply appraise the different aspects of PHPT, providing an update of recent scientific and clinical evidence on the hot topics of this endocrine disease. We invite investigators to contribute original research articles, as well as review articles and clinical case presentations, that explore the critical aspects of PHPT.

Potential topics include but are not limited to the following:

• Asymptomatic primary hyperparathyroidism and normocalcemic variant of PHPT (NPHPT) management
• Severe forms of primary hyperparathyroidism, including atypical parathyroid adenoma and parathyroid carcinoma
• Management of familial hyperparathyroid syndromes: pathogenesis and clinical features, diagnostic procedures, and surgical and pharmacological approaches
• Imaging techniques in primary hyperparathyroidism for preoperative localization
• Surgical therapy and approaches in primary hyperparathyroidism
• Management of persistent/recurrent primary hyperparathyroidism
• Relationship between renin-angiotensin-aldosterone system and parathyroid hormone
• Pharmacological options for medical management of primary hyperparathyroidism