Primary hyperparathyroidism (PHPT) most commonly occurs sporadically, typically caused by a parathyroid adenoma. Such cases are more common in women and with increasing age. Other risk factors include neck irradiation and lithium use. Inherited cases can occur in relation to genetic conditions including MEN1. Parathyroid carcinoma is vanishingly rare. PHPT may present with symptoms of hypercalcaemia (such as thirst, excessive urination or constipation), or evidence of potential end organ effects. However, the most common presentation is an incidental finding of a raised albumin-adjusted serum calcium.