PITUITARY-ADENOMAS - RECENT ADVANCES IN CLASSIFICATION, HISTOPATHOLOGY AND MOLECULAR-BIOLOGY

Research efforts during the past decade have brought forth new and substantial insights into the biology, pathology, and pathogenesis of pituitary neoplasms. Some of these advances have culminated in a new classification system which combines immunohistochemical methods with electron microscopy and permits, for the first time, classification of pituitary tumors on the basis of fundamental structure-function relationships. More recently, with the introduction of molecular biological techniques, a number of growth factors and oncogenes have been implicated in the genesis of pituitary tumors. This paper attempts to review current knowledge of the biology and histopathology of pituitary tumors. As a primary aim, the new classification system of pituitary tumors which favors structure-function relationships will be reviewed in detail. In addition, a discussion of the current knowledge of aberrant molecular physiology identified in pituitary tumors will also be presented. This includes the role of growth factors, signal transducers and putative oncogenes relevant to the pathogenesis of these tumors.