Pituitary tumors represent a heterogeneous group of neoplasms by histotype. The pituitary adenomas are the most frequent heteroformation, among those affecting the pituitary gland, followed by meningiomas, craniopharyngiomas, germosomes and tumours secondary, such as metastases and lymphomas. Since these conditions are considered rare, the data epidemiology and prognosis to predict the natural history of these diseases can not be considered conclusive. Pituitary adenomas are a useful model for epidemiology in the study of pathology pituitary. Over the past 20 years, several attempts have been made to identify unique prognostic factors, which predict the outcome of these pathologies, but without To arrive at a definitive classification. The purpose of this study aims to collect clinical, biochemical, morphological and pathological data on the retrospective and prospective cohort of over 1600 patients undergoing neurosurgical removal of pituitary tumors in the last 20 years, to develop a prognostic classification.