Pituitary apoplexy is attached to the hypothalamus, a part of the brain, by a stalk that also contains the blood vessels that supply the gland. It is unclear why pituitary tumors are five times more likely to bleed than other tumors in the brain. There are various proposed mechanisms by which a tumor can increase the risk of either infarction (insufficient blood supply leading to tissue dysfunction) or hemorrhage. The pituitary gland normally derives its blood supply from vessels that pass through the hypothalamus, but tumors develop a blood supply from the nearby inferior hypophyseal artery that generates a higher blood pressure,
Pituitary adenoma only, with no other associated symptoms that occur in Multiple endocrine neoplasia Type 1 or Carney complex. FIPA was first described in a limited cohort of families by group in Liège, Belgium ; later FIPA was fully characterized in a multicenter international study of 64 families. FIPA families are divided into those that are homogenous and have the same type of pituitary adenoma in all the affected family members (e.g. only acromegaly, only prolactinoma, etc) , while heterogeneous FIPA families can have different pituitary adenomas in affected family members. FIPA has two known genetic causes, mutations in the "aryl hydrocarbon