The role of molecular pathology in the classification and clinicopathologic evaluation of pituitary neoplasms

Pituitary tumors are frequently occurring, most often slowly growing, noninvasive, benign neoplasms. Several types can be distinguished based on their clinical presentation, hormone secretion, growth potential and morphology. The present article describes the pituitary gland and their adenomas based on their morphological characteristics including histologic, immunohistochemical and molecular/genetic profiles. It outlines both the clinically functioning as well as the non-functioning adenomas. Many new molecular profiles have been elucidated in pituitary adenomas in the past decade. Some of these new findings emphasize the unique molecular events in different types of pituitary adenomas, although many common pathways have also been reported. The descriptions in this review can be utilized by clinicians, pathologists and researchers as a diagnostic tool to establish diagnosis and classification of various pituitary tumor types.