Master of all endocrine activity and executive organ of one's quality of life, the pituitary gland is tightly lodged in the" turkish saddle. " As a bony container, the sella turcica is to the hypophysis what the skull is to the brain; it can therefore be looked upon as a little vault within the cranial vault. Just as the cranium is moulded by the growth of the brain, so is the sella fashioned by its content. It becomes locally enlarged in response to expanding intrasellar lesions, and it tends to return to its original size and shape upon their removal or destruction. Pituitary adenomas have in the past been diagnosed upon enlargement of the sella turcica. In the past decade, as a direct result of interdisciplinary coopera- tion, we have learned that tiny adenomas, the immediate cause of some cases of acromegaly, amenorrhea-galactorrhea syndrome, or Cushing's disease, can exist with minimal or no observable effect on the size of the sella. The break- through started when radioimmunoassay, as a new method of accurately measur- ing specific hormonal output, indicated selective pituitary oversecretions in pa- tients with normal-sized sellae. Neurosurgeons highly skilled in the transsphenoi- dal approach with the surgical microscope were obliged to operate on some of these patients and confirmed the presence of tiny oversecreting adenomas in their pituitary glands.