Giant double parathyroid adenoma presenting as a hypercalcaemic crisis.

The largest documented case of a double parathyroid adenoma is reported. The patient presented in hypercalcaemic crisis with a large intrathoracic mass. After removal of a massive cystic parathyroid adenoma from the right superior mediastinum, a second very large parathyroid adenoma was found on the contralateral side adjacent to the left thyroid lobe. This case illustrates the importance of the cervical approach, as well as routine bilateral neck exploration, for all cases of primary hyperparathyroidism.