IMMUNOHISTOCHEMICAL CLASSIFICATION AND ULTRASTRUCTURAL STUDY OF HYPERPARATHYROIDISM

Abstract

Immunohistochemical and ultrastructural studies were performed on cases with hyperparathyroidism. The relationship between histology and cell activity in hyperfunctioning parathyroid glands was studied. Furthermore, the synthesis-secretion process of parathyroid hormone (PTH), which has been more or less elucidated biochemically, was studies by a morphological means. The subjects employed in the present study were 23 cases of primary hyperparathyroidism (PHPT) and 31 cases of secondary hyperparathyroidism (SHPT). Based on the results of the immunohistochemical study using anti-PTH antibody, the histology of the parathyroid gland was classified into 4 types: type A; sporadic cells showing intense yellowish brown staining in their cytoplasm, type B; glandular cells showing intense yellowish brown staining specifically in their cytoplasm, type C; as a whole the cells were weakly stained, but intensely stained cells were absent, and type D; only the cytoplasm of large cells showed uniform and intense yellowish brown staining. In both PHPT and SHPT, type C constituted about 80%. On the other hand, all water clear cell hyperplasia in SHPT showed type D staining. Electron microscopic studies performed on the hyperparathyroidism revealed that the rough endoplasmic reticulum and Golgi apparatus, which are related to the synthesis of PTH, were well developed. Immunoelectron microscopy revealed that only the secretory granules were specifically stained with the anti-PTH antibody. This finding suggests that PTH becomes active once it reaches the secretory granule.