DOUBLE PARATHYROID ADENOMAS - CLINICAL AND BIOCHEMICAL CHARACTERISTICS BEFORE AND AFTER PARATHYROIDECTOMY

Objective There is considerable debate about whether double parathyroi d adenomas are a discrete entity or represent hyperplasia with parathy roid glands of varying sizes. This distinction is important because it impacts on the extent of parathyroid resection and the success of the parathyroid operation. Summary Background Data Double parathyroid ade nomas have been reported to occur in 1.7% to 9% of patients with prima ry hyperparathyroidism (HPT). It is important for surgeons to differen tiate between double adenoma and hyperplasia with glands of varying si zes using gross examination during the initial procedure because micro scopic findings of a small biopsy specimen at frozen-section examinati on may not be diagnostic. Methods From 1982 to 1992, 416 unselected pa tients (309 women and 107 men) with primary HPT without familial HPT o r multiple endocrine neoplasia (MEN) were treated by one surgeon at th e University of California at San Francisco. Double adenoma occurred i n 49 patients, solitary adenoma in 309 patients, and hyperplasia in 58 patients. The authors analyzed the clinical manifestations, the preop erative and postoperative serum levels of calcium, phosphate, and para thyroid hormone (PTH), and the success rate and outcome after parathyr oidectomy and compared their results in 49 patients with double adenom as to the results for patients with solitary adenomas or hyperplasia. Results Ten of the patients with double adenomas (20.4%) were referred for persistent HPT after removal of one abnormal parathyroid gland. T he ages of the patients with double adenoma, single adenoma, and hyper plasia were 61 +/- 14, 56 +/- 15, and 58 +/- 7 years, respectively. Fa tigue, muscle weakness, and bone pain were common in patients with dou ble adenomas, whereas nephrolithiasis occurred more frequently in pati ents with solitary adenoma (p = 0.0001). Serum calcium and PTH levels (per cent of upper limit of normal) fell from 11.5 +/- 1.2 mg/dL and 4 87% to 9.5 +/- 0.8 mg/dL and 61% for patients with double adenomas; fr om 11.4 +/- 0.9 mg/dL and 378% to 9.3 +/- 1.4 mg/dL and 1 01 % for pat ients with single adenoma; and from 10.9 +/- 0.5 mg/dL and 418% to 9.1 +/-0.7 mg/dL and 94% for patients with hyperplasia, respectively. The re was no recurrence in the patients with double adenomas with a mean follow-up time of 5.8 years. Conclusions Double adenomas are a discret e entity and occur more often in older patients. Patients with double adenomas can be successfully treated by removal of the two abnormal gl ands.