Mediastinal hyperfunctioning parathyroid adenoma.

A patient presented with peptic ulcer disease and nephrolithiasis. Laboratory investigation disclosed hyperparathyroidism and following neck exploration, hypercalcemia persisted. After two years' follow-up, a retroesophageal mass that proved to be a parathyroid adenoma was discovered. This case is presented to illustrate the unusual occurrence of a posterior mediastinal tumor and the difficulty in managing ectopic parathyroid adenomas.