Intraoperative histologic evaluation in exploration of the parathyroid glands.

In this review, 123 explorations for primary hyperparathyroidism were performed, at which at least three glands were identified and specimens were taken for biopsy. Gross operative and histologic findings were evaluated and correlated with follow-up data. A new classification for disease of the parathyroid glands is devised in which microhyperplasia occurring in grossly normal glands is subclassified into two groups. One (Class II), consisting of hypercellularity only, is thought not to produce clinical hyperparathyroidism. The second group (Class III), which includes glands with nodular hyperplasia, abnormal cytologic findings or oxyphilic nodules, is considered clinically significant. Evaluation and follow-up study revealed three instances of clinical hyperparathyroidism attributed to Class III histologic changes, while there were no instances of recurrent or persistent hyperparathyroidism attributable to Class II disease. Involvement of multiple glands, both gross and microscopic, occurred frequently (26 per cent) and was often bilateral and nonuniform. We concluded that optimal surgical management of primary hyperparathyroidism is achieved by selective removal of parathyroid glands guided by the histologic findings in each gland.