Massive parathyroid hemorrhage in a case of water-clear cell hyperplasia.

A case of water-clear cell hyperplasia of the parathyroid glands is reported. As far as we know this case is unique in respect of the following features. All the parathyroids were located in the superior mediastinum. One abnormal parathyroid gland was removed with the help of a mediastinoscope. The patient survived a massive parathyroid hemorrhage. This case draws attention to the facts that enlarged parathyroid glands can appear as mediastinal tumours and that massive bleeding can occur in abnormal parathyroid glands.