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Academia Mexicana de Neurología, A.C.

2006, Number 6

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Rev Mex Neuroci 2006; 7 (6)

Hypophysis tumors

Escobar A

Language: Spanish
References: 16
Page: 586-591
PDF size: 73.77 Kb.


ABSTRACT

The pituitary gland or hypophysis cerebri is a small structure similar to a hazelnut. Its dimensions are 13 x 10 x 6 mm, it weighs 650 mg, is formed by both glandular tissue the adenohypophysis and nervous tissue the neurohypophysis, it is found at the base of the skull in the sella turcica on the superior surface of the body of the sphenoid bone. Anatomically and functionally associated to the hypothalamus constitutes the so-called endocrine brain five important hormones essential for somatic development, metabolism and endocrine homeostasis are synthetized in the glandular part: growth hormone, adrenocorticotropin, thyrotropin, prolactin and the gonadotropins –follicle stimulating hormone and luteinizing hormone. From the posterior lobe of the hypophysis the hypothalamohypophyseal tract carries into the circulatory system the vasopressin and oxytocin hormones, neurosecretory product of the paired supraoptic and paraventricular hypothalamic nuclei. The majority of the pituitary tumors are originated in the adenohypophysis; tumors originating in the neurohypophysis are extremely rare. Immunecytochemistry and immunehistochemistry techniques led to a more precise and modern classification of pituitary tumors. The classification is based on the type of hormone produced by the tumoral cells: hence they may be growth-hormone adenomas, prolactin, adrenocorticotropin, thyrotropin and gonadotropin adenomas. It is also possible to find adenomas producing more than one hormone, those tumors are called mixed adenomas or plurihormonal adenomas. Although benign adenomas represent the overwhelming majority of the adenohypophyseal neoplastic lesions, the adenomas may also be invasive pituitary adenomas and pituitary carcinomas. Tumors originating in the posterior lobe are extremely rare, only choristoma (hamartoma) and granular cell myoblastoma derived from pituicytes have been described, the latter may be considered a form of gliomas.


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