[Mediastinal parathyroid cyst].

A 66-year-old woman, having no complaint, admitted our clinic, because of a mass in the right superior mediastinum detected three years ago on chest X-ray. The operation was performed through the right thoracotomy in December of 1989. The thin-walled cyst located adjacent to the trachea between superior vena cava and back bones, occupied from beneath the innominate artery to the right main bronchus. The tumor (7 x 5 x 5 cm) weighing 80 grams had a smooth surface and contained watery fluid. Histological examination showed a cyst lined a monolayer of cuboidal epithelium. The cyst wall consisted of parathyroid tissue. Mediastinal parathyroid cyst is very rare. Since the first report of DeQuervain, 15 cases have been reported. These reports are reviewed.