Pathology of pituitary tumors.

Pituitary adenomas are benign neoplasms originating in adenohypophysial cells. They represent the most common neoplasm of the sellar region, comprising approximately 15% of all primary intracranial tumors. Depending on the studies of unselected adult autopsy material, their frequency as an incidental finding varies between 5% and 20%. The first part of this article summarizes the immunohistochemistry of nontumorous human adenohypophysis. In the second part, the classification of pituitary tumors is discussed, followed by the immunohistochemical and electron microscopic findings of pituitary adenomas and pituitary carcinomas.