The fine structure of the human pituitary chromophobe adenoma with special reference to the classification of this tumor.

It is generally accepted that the human pituitary chromophobe adenoma has no secretory function because of its exhibiting no distinctly stained granules in the light microscopy. On the other hand, the recent electron microscopic studies have proved the presence of the secretory granules in this tumor (CARDELL and KNIGHTON, 1966; FUKUMITSU, 1964; LUSE, 1962; GUSEK, 1962; SCHELIN, 1962; WECHSLER and HossMANN, 1965). These findings suggest that the chromophobe adenoma may carry on a secretory production in some way, and that this tumor may be divided into some subtypes according to the morphology of the secretory granules contained. The purpose of the present study is to verify the secretory activity in this tumor by examining its fine structure with an electron microscope. Furthermore, in this