[Parathyroid cyst of the anterior mediastinum].

A mediastinal cyst measuring 6 cm was removed by manubriotomy in a 66-year-old woman. This patient had no clinical or biological evidence of hyperparathyroidism. The cyst was close to the thymus and compressed the innominate venous trunk. It contained a clear fluid. Normal parathyroid tissue was present in the capsular wall that was fibrous and partially calcified. This cysts are rare and their mediastinal localization is exceptional.