Macroadenomas usually present clinically with signs and symptoms associated with the displacement of the optic chiasm, cavernous sinus, and hypothalamus. Pituitary microadenomas have a surprisingly high incidence and are present in approximately twenty-five per cent of all patients examined at autopsy. It is now known that, in life, only the minority (less than ten per cent) progress to form macroadenomas. Since microadenomas are small in size, such tumours are only very occasionally associated with hypopituitarism.
