The pathogenesis of hypophyseal fibrosis in aging: its relationship to tissue iron deposition.

An investigation was made of 101 hypophyses from male and female human subjects dying from unrelated diseases. Careful microscopic examination revealed that fibrous replacement of the gland begins after the fourth decade. There is a gradual increase in iron deposition in this connective tissue after the 4th decade. It is suggested that the fibrous replacement of the hypophysis is a consequence of repeated bouts of passive congestion with diapedesis of red cells through the walls of anoxic capillaries. This pattern is akin to that of brown induration of the lung. In this manner, the active cells of the hypophysis may gradually be replaced by collagenous tissue. Because of the inherent slowness of this process, the gland seems to adapt quite well to a reduction in functional elements, thus circumventing significant clinical effects.