Late results of operation for primary hyperparathyroidism in 441 patients.

The late results of operation for primary hyperparathyroidism (HPT) were analyzed in 441 patients operated on 4 to 27 years earlier (mean follow-up time, 7.7 years). A conservative surgical approach was mainly used, attempting if possible to visualize all four parathyroid glands and extirpate only the enlarged glands. Subtotal resection was performed in patients with hyperplasia. The histopathologic diagnosis was adenoma in 77% and hyperplasia in 18%. In 5% of the patients, the histopathologic classification was uncertain. Hypercalcemia persisted after operation in 8% of all patients. This generally occurred because of an incomplete neck exploration or too limited a resection in the patients with hyperplasia. Recurrent hypercalcemia occurred in 16% of the patients operated on for hyperplasia and was noted 1 to 19 years after surgery. Recurrences were also seen in 3% of the patients with adenomas but not earlier than 9 years after the operation. These findings suggest that primary HPT may even in patients with adenomatous disease, sometimes affect all parathyroid glands. Nevertheless, it was obvious that most of the patients with adenomas would not have benefited from a more radical procedure. On the other hand, it was evidently important to obtain a correct histopathologic diagnosis intraoperatively so that patients with hyperplasia could be identified and adequatley treated.