Neurohypophysis

The posterior pituitary (or neurohypophysis) is a lobe of the pituitary gland that is functionally connected to the hypothalamus by the median eminence via a small tube called the pituitary stalk (also called the infundibular stalk or the infundibulum).

Anatomically, the neurohypophysis consists of the posterior pituitary gland, pituitary stalk, infundibulum, and median eminence. The cellular elements include pituicytes, microglias, and the distal parts of nerve cells from anastomosed blood vessels and the hypothalamus.

The 2022 World Health Organization classification of tumors of the pituitary gland distinguishes the anterior lobe of the pituitary gland (Adenohypophysis) from the posterior lobe (neurohypophysis) and hypothalamic tumors.

Anterior lobe tumors include (i) well-differentiated adenohypophyseal tumors that are now classified as pituitary neuroendocrine tumors (PitNETs; formerly known as pituitary neuroendocrine tumors), (ii) pituitary blastoma, and (iii) the two types of craniopharyngioma.