The pituitary gland is very small, less than half an inch in diameter. Despite its small size, it is often referred to as the master gland. It is two organs in one. The anterior pituitary releases several important hormones such as growth hormone, as well as hormones which instruct other endocrine organs to release their respective hormones (such as thyroid stimulating hormone). The posterior pituitary gland is in direct continuity with the brain and releases two hormones, oxytocin which stimulates milk production during nursing and uterine contraction during labor, and vasopressin (antidiuretic hormone, ADH) which causes resorption of water from the kidney tubules. The pathologist is often called upon to evaluate the pituitary for the presence of an adenoma. This is a benign tumor but by virtue of its size and growth, may compress the optic nerve and other structures nearby, causing symptoms. A frozen section is often performed to confirm the presence of pituitary tissue and confirm the neoplasm.
Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH)
HISTOPATHOLOGICAL VARIANTS CHARACTERIZATION LYMPHOCYTIC HYPOPHYSITIS
Immunocytochemical localization of mast cells in lymphocytic hypophysitis.
Vidal S, Rotondo F, Horvath E, Kovacs K, Scheithauer BW.
Department of Laboratory Medicine, St Michael's Hospital, Toronto, Ontario, Canada.
Am J Clin Pathol 2002 Mar;117(3):478-83 Abstract quote
We studied 15 transsphenoidally resected pituitary tissues diagnosed by histologic examination as chronic lymphocytic hypophysitis.
Six autopsy-obtained pituitaries of patients who died of nonendocrine diseases also were studied. Tryptase immunohistochemical analysis, which specifically identifies mast cells, demonstrated numerous, randomly distributed multifunctional cells throughout the inflammatory reaction. Several mast cells were located in the vicinity of capillaries; several others were distributed far from the blood vessels. Occasional mast cells also were noted in the nonpathologic anterior and posterior pituitary lobes. Morphometric analysis confirmed that in lymphocytic hypophysitis, the number of mast cells per volume of tissue was significantly increased compared with that of nonpathologic anterior and posterior pituitary lobes.
To elucidate the possible role of mast cells in chronic lymphocytic hypophysitis, microvessel densities were assessed quantitatively using immunohistochemical analysis for CD34, a sensitive marker of endothelial cells. The strong positive correlation between numeric density of mast cells and microvessel density per volume of pituitary tissue suggests that mast cell-derived products may influence capillary permeability and angiogenesis, thereby facilitating the access of inflammatory cells to adenohypophysial cells.
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Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.
Robbins Pathologic Basis of Disease. Sixth Edition. WB Saunders 1999.
Crank Case Oil-Gross descriptive term sometimes used to describe the dark oily appearance of a craniopharyngioma, a tumor arising within the hypothalamus.
Microadenoma-A pituitary adenoma less than 10 mm in diameter.
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Last Updated 1/9/2003
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