Ultrastructure of chromophobe adenoma of the human pituitary gland

Abstract

Sixteen specimens of pituitary adenoma were studied by EM. Twelve of them were nonfunctioning tumors and 4 were associated with acromegaly. All tumors showed the light microscopic appearance of classical chromophobe adenoma. Though EM revealed varying degrees of granularity in the majority of cells in all tumors, 2 distinct morphological types of chromophobe tumors were observed. In 1 type, secretory granules were frequently seen in moderate or large numbers and the cells were poor in RER [rough endoplasmic reticulum] and Golgi apparatus. These cells are considered to be secretorily inactive storage cells and they were the predominant cells in 8 cases of nonfunctioning adenomas.