IMMUNOREACTIVE CHARACTERISTICS AND CLASSIFICATION OF HYPERPARATHYROIDISM

Hyperparathyroidism is caused mainly by three different conditions: na mely, secondary hyperplasia, primary hyperplasia, and adenoma with onl y a few cases due to carcinomas. Histological distinction among these diseases is still difficult. In an attempt to characterize the three c onditions, 17 cases from patients with hyperparathyroidism and 12 with normal glands were investigated immunohistochemically using antibodie s against PTH, PTHrP, Ki-67 (MIB-1), and chromogranin A. The normal gl ands showed a diffuse staining pattern for PTH, and focal staining for PTHrP and for chromogranin A. Secondary hyperplasia demonstrated eith er focal, diffuse, or mixed staining in one gland with the three antib odies. For the primary hyperplasias and adenomas, the cases could be d ivided into two groups. The first group (group I), including 1 case of primary hyperplasia and 3 cases of adenoma, showed a homogeneous stai ning pattern with all three antibodies. A heterogeneous staining patte rn similar to secondary hyperplasia was found in the other 8 cases tha t formed the second group (group II). There were five types of cytolog ic staining patterns after immunostaining. In secondary hyperplasia an d group II, several patterns appeared simultaneously. On the contrary, only one pattern was found in group I. The proliferative index (PI) f rom Ki-67 staining of group I was also significantly higher than in gr oup II. A lower PI was observed in the normal glands. The present resu lts indicate that different immunohistochemical characteristics exist in primary hyperplasias and in adenomas.