THE IMPORTANCE OF THE TEAM WORK IN DIAGNOSIS OF PITUITARY ADENOMAS: THE FIVE-TIER WORLD HEALTH ORGANIZATION CLASSIFICATION

Abstract

Summary. In the last ten years great changes occurred concerning the basic knowledge on pituitary adenomas. Many different classifications of pituitary adenomas were proposed. In 2000 World Health Organization accepted the five-tier classification of pituitary adenomas proposed by Kovacs and Horvath. It is based on clinical and biochemical results, neuroradiological imaging, operative findings, pathohistological examination, immunocytochemistry and electron microscopy studies on more than 10 000 surgically treated pituitary adenomas. Its importance is that it supplies the endocrinologist, neurosurgeon and oncologist with valuable information concerning the biological behavior, growth potential, treatment response and prognosis of pituitary ade- nomas. Due to the financial restraints, lack of facilities and unavailability of well trained personnel this five-tier classification cannot be fully implemented at our institution. Nonetheless, a perfectly useful diagnosis may be made in instances of limited sources. Clinical, biochemical, neuroradiological and intraoperative data coupled with basic histology are fundamental. Together with the novel biological techniques that provide the data on tumor’s growth rate, aggressiveness and invasiveness, they are necessary in establishing the correct diagnosis which will direct patient’s future treatment. We strongly advocate in favor of this five-tier classification of pituitary neoplasms and hope it will reach the full implementation.