Parathyroid cysts: a report of eleven cases including two associated with hyperparathyroid crisis.

Eleven parathyroid cysts were found in 325 patients who underwent parathyroid operations. Ten cysts were located in the neck and one was located in the mediastinum. The cysts ranged in size from 1.6 to 10 cm with a mean of 3.9 cm. The patients who had cysts included six women and five men, and their ages ranged from 28 to 72 years with a mean of 51 years. In contrast to other reports that have suggested that most parathyroid cysts are nonfunctional, all but one of our patients had hyperparathyroidism, as evidenced by hypercalcemia, hypophosphatemia, and elevated parathyroid hormone level, which was corrected by cyst removal. The nonfunctional cyst first appeared to be an asymptomatic neck mass. Two patients had acute hyperparathyroid crises, which required emergency operations. It is postulated that the crises may have been the result of spontaneous necrosis of preexisting parathyroid adenomas. This is supported by the pathologic findings of degeneration and early organization as well as by the presence within the cyst of sanguineous fluid that contained a parathormone concentration greater than 100 times normal serum levels.