Other combinations of bihormonal secretion are reported; they are sometimes underestimated. Plurihormonal secretion in pituitary adenomas is usually under estimated; it is in most cases subclinical. Demonstration of hormones, transcription factors for functional differentiation and proliferation index have an important role in the classification, prediction and treatment of these adenomas, as the demonstration of neuroendocrine differentiation. IHC is frequently not performed and the accurate classification and prognosis of these adenomas remains obscure.