Hyperparathyroid crisis is a rare manifestation of parathyroid disease. We present the case of a 53-year-old gentleman with a review of the current literature. He presented in acute renal failure with epigastric pain and vomiting. His serum-corrected calcium (CCa(2+)) was raised at 5.2 mmol/L, in addition to a massively raised parathyroid hormone (PTH) level (3957 ng/L). Ultrasound studies of the neck revealed a 2 cm well-defined mass inferoposterior to right thyroid lobe. CT scans of the neck showed a normal mediastinum and confirmed no associated lymphadenopathy. Having undergone medical resuscitation for 9 days, a neck exploration revealed a cystic mass, which was excised. Histological investigations revealed a 9.25 g, cystic parathyroid adenoma with no features of malignancy. His PTH and CCa(2+) returned to normal postoperatively. This suspicious presentation of benign disease, including a marked elevation in PTH, highlights the challenges facing the endocrine surgeon in dealing with parathyroid disease.