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Parathyroid Cyst of the Mediastinum

PARATHYROID cysts are uncommon causes of clinically significant masses in the neck, and are rare causes of mediastinal spaceoccupying lesions. Since Goris 16 first described the excision of a parathyroid cyst in 1905, only 58 cases have appeared in the literature. All but eight of the reported cases have been located in the region of the inferior parathyroids, and are consistently described by the surgeon as being loosely attached to the lower thyroid pole, and easily separated from the thyroid gland. Atypical locations of the cysts were as follows: in the position of the superior parathyroids; between the sternomastoid muscle and angle of the mandible; posterior to the thyroid gland; and in the anterior superior mediastinum. Only nine of the reported cases extended into the mediastinum (Table 1). De Quervain 10 reported the first case of a substernal parathyroid cyst in 1925, and only two of the subsequently reported cases 22, 23 have been purely mediastinal in location. We wish to add a case of parathyroid cyst of the anterior superior mediastinum, and to call attention to this lesion as one to be included in the differential diagnosis of space-taking masses in the superior chest.