Pituitary neoplasms probably constitute 8 to 13 percent of intracranial tumors; incidence in Cushing’s series (62) was 22.3% during 30 years but this is inordinately high, due obviously to his known interest in the clinical problems presented by the hypophysis. The tumors of the pituitary gland itself are three: adenoma, craniopharyngioma, and carcinoma (named in order of their frequency), but there also occur in the region of the sella several other groups of pathologic processes which inevitably must be considered in differential surgical diagnosis. It is customary therefore to regard pituitary neoplasms clinically as but one of the anatomic components of a basic chiasmal syndrome which will be discussed later 1.