Abstract
The human pituitary chromophobe adenomas obtained from 19 patients were studied with the electron microscope.
The secretory granules are always found in the tumor cells although they vary in number. The chromophobe adenomas can be classified electron microscopically into two types according to the size and appearance of the secretory granules. One type of tumor has dense and solid granules about 250mμ in diameter and the other type of tumor contains granules about 150mμ in diameter of various appearance, such as solid granules, haloed granules and empty vesicles. It may be presumed that the former granules correspond to the acidophil granules and the latter to the ACTH granules.
The tumor cells show considerably irregular shape and often have complex processes. The general morphology of them is almost similar to that of the “chromophil” cells in animal and human anterior pituitary, but besides the general cell organelles, several such particular organelles are not rarely found, as annulate lamellae, cilia, microtubules and membrane-particle arrays.
Furthermore, the findings indicate that the chromophobe adenoma cells may carry on an active secretory production in the same way as in the normal anterior pituitary and that the secretory granules may be discharged into the extracellular space by merocrine secretion.
