A 24-year-old man with primary hyperparathyroidism and osteitis fibrosa cystica developed acute hypocalcaemia. Spontaneous healing of his bone disease was confirmed radiographically and by correction of the serum alkaline phosphatase. Hypercalcaemia associated with a raised serum parathyroid hormone recurred 90 weeks after the initial presentation. During the fourth neck exploration a parathyroid adenoma was removed, resulting in resolution of his condition. Haemorrhagic infarction of an adenoma was the most likely cause of the acute hypocalcaemic episode.