This monograph represents a comprehensive review of the various tumors and tumorlike lesions that involve the pituitary gland and the sellar region. It features a clinicopathologic approach to the diagnosis of pituitary adenomas and a systematic review of other sellar and parasellar tumors that present with mass effects and/or endocrine syndromes. The text reviews normal anatomy, embryology, and cytology as well as hormonal function and regulation. New Aspects of the molecular regulation of cell differentiation and hormone function are included. One chapter is dedicated to practical issues of specimens handling, including the diagnostic roles of intraoperative consultation, conventional histology and special stains, immunohistochemical, electron microscopy, genetic analysis, and other techniques. Clinicopathologic correlates in pituitary adenomas are emphasized, with descriptions and illustrations of clinical manifestations, biochemical data, and radiological findings relevant to the pathological diagnosis of all major entities. Morphologic features of each tumor are lavishly illustrated; differential diagnosis are discussed in detail; and a large portion of the monograph is dedicated to other tumors and non-neoplastic lesions that occur in the region of the sella turcica. Prognostic implications and therapeutic approaches are reviewed for each pathological entity. Every chapter has an extensive and up-to-date bibliography. In 214 pages and 295 figures (200 in color), this volume emphasizes practical issues in diagnosis and potential pitfalls, while including essential basic information. This fascicle will serve as a valuable resource for pathologists as well as endocrinologists, neurologists, neurosurgeons, radiologists, and scientists with an interest in the diagnosis, cytogenesis, and pathogenesis of pituitary disease.