Hypercalcaemia. The case of the missing adenoma

A case of severe hypercalcaemia is described. The biochemical picture strongly suggested primary hyperparathyroidism, yet no adenoma could be found in the neck or upper mediastinum. The tumour was eventually demonstrated by computerized tomographic scan and was removed at surgery from the posterior mediastinum beneath the arch of the aorta. Preoperative and postoperative problems of the case are discussed.