Pituitary gland Rathke's pouch. This contrasts with the posterior pituitary, which originates from neuroectoderm. Endocrine cells of the anterior pituitary are controlled by regulatory hormones released by parvocellular neurosecretory cells in the hypothalamic capillaries leading to infundibular blood vessels, which in turn lead to a second capillary bed in the anterior pituitary. This vascular relationship constitutes the hypothalamo-hypophyseal portal system. Diffusing out of the second capillary bed, the hypothalamic releasing hormones then bind to anterior pituitary endocrine cells, upregulating or downregulating their release of hormones. The anterior lobe of the pituitary can be divided into the pars tuberalis (pars glandularis) and pars
Pituitary adenoma presented above. Tumors which cause visual difficulty are likely to be a "macroadenoma" greater than 10 mm in diameter; tumors less than 10 mm are "microadenoma". The differential diagnosis includes pituitary tuberculoma, especially in developing countries and in immumocompromised patients. The diagnosis is confirmed by testing hormone levels, and by radiographic imaging of the pituitary (for example, by CT scan or MRI). Unlike tumors of the posterior Pituitary, Pituitary adenomas are classified as endocrine tumors (not brain tumors). Pituitary adenomas are classified based upon anatomical, histological and functional criteria. Pituitary incidentalomas are pituitary tumors that are characterized as an incidental