Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 10% of intracranial neoplasms. They often remain undiagnosed, and small pituitary tumors are found in 6 to 24 percent of adults at autopsy. The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... See the article about cancer for the main article about malignant tumors. ... Located at the base of the skull, the pituitary gland is protected by a bony structure called the sella turcica. ... Neoplasia (literally: new growth) is abnormal, disorganized growth in a tissue or organ, usually forming a distinct mass. ...

Types

Pituitary tumors were, historically, classed as basophilic, acidophilic, or chromophobic on the basis of whether or not they took up the stains hematoxylin and eosin. This classification has fallen into disuse, in favor of a classification based on what type of hormone is secreted by the tumor (though tumors which do not secrete any active hormone ("non-functioning tumors") are still sometimes called "chromophobic"). Basophilic is a technical term used by histologists. ... Acidophilic describes the tendency of a inorganic particle or organism to acidic conditions or acids. ... Haematoxylin is extracted from the wood of the logwood tree. ... Eosin is an orange-pink dye derived from coal tar. ... A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ...

At present, classification of pituitary tumors is based on plasma hormone levels or immunohistochemical staining:

• corticotrophic adenomas secrete adrenocorticotropic hormone (ACTH) and pro-opiomelanocortin (POMC)
• somatotrophic adenomas secrete growth hormone (GH)
• thyrotrophic adenomas secrete thyroid-stimulating hormone (TSH)

This is a rare tumor type, making up <1% of all pituitary adenomas. TSH secretion from these tumors can cause hyperthroidism.^[1]

• gonadotrophic adenomas secrete luteinizing hormone (LH), follicle-stimulating hormone (FSH) and their subunits
• lactrotrophic adenomas or prolactinomas secrete prolactin
• null cell adenomas do not secrete hormones, but may stain positive for synaptophysin

Adrenocorticotropic hormone (ACTH or corticotropin) is a polypeptide hormone secreted from corticotropes in the anterior lobe of the pituitary gland in response to corticotropin-releasing hormone (CRH) released by the hypothalamus. ... Pro-opiomelanocortin (POMC) is a precursor polypeptide that is built of 241 amino acid residues. ... The two-letter abbreviation GH has several different meanings: Growth hormone the IATA code for Ghana Airways Guitar Hero (VG) This page expands and disambiguates a two-letter combination which might be an abbreviation, an English word, a word in another language, any or all of these. ... Thyroid-stimulating hormone (also known as TSH or thyrotropin) is a hormone produced by thyrotrope cells in the anterior pituitary gland which regulates the endocrine function of the thyroid gland. ... Luteinizing hormone (LH) is a hormone released by gonadotropes in the anterior lobe of the pituitary gland. ... Follicle stimulating hormone (FSH) is a hormone produced by gonadotropes in the anterior pituitary gland. ... A prolactinoma is a benign tumor (adenoma) of the pituitary gland that produces a hormone called prolactin. ... Prolactin is a hormone synthesised and secreted by lactotrope cells in the adenohypophysis (anterior pituitary gland). ... Synaptophysin is a synaptic vesicle glycoprotein weighing 38 kDa. ...

Diagnosis

The diagnosis is generally entertained either on the basis of visual difficulties arising from the compression of the optic nerve by the tumor, or on the basis of manifestations of excess hormone secretion: the specifics depend on the type of hormone. Tumors which cause visual difficulty are likely to be macroadenomas greater than 10 mm in diameter; tumors less than 10 mm are microadenomas. The optic nerve is the nerve that transmits visual information from the retina to the brain. ...

The most common secretory pituitary tumor is the prolactinoma, which can cause galactorrhea, hypogonadism, amenorrhea, infertility, and impotence. GH-secreting tumors cause acromegaly (gigantism). Corticotrophic adenomas cause Cushing's disease. TSH-secreting adenomas can, rarely, cause hyperthyroidism. Tumors which secrete LH, FSH or TSH most often don't cause symptoms because of that hormone secretion. Some tumors secrete more than one hormone, the most common combination being GH and prolactin. Galactorrhea or galactorrhoea is the spontaneous flow of milk from the breast, unassociated with childbirth or nursing. ... Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ... Amenorrhoea (BE) or amenorrhea (AmE) is the absence of a menstrual period in a woman of reproductive age. ... Infertility is the inability to naturally conceive a child or the inability to carry a pregnancy to term. ... Impotence or, more clinically, erectile dysfunction is the inability to develop or maintain an erection of the penis for satisfactory sexual intercourse regardless of the capability of ejaculation. ... Acromegaly (from Greek akros high and megalos large - extremities enlargement) is a hormonal disorder that results when the pituitary gland produces excess growth hormone (hGH). ... Cushings syndrome or hypercortisolism is an endocrine disorder caused by excessive levels of the endogenous corticosteroid hormone cortisol. ...

Prolactinomas are frequently diagnosed during pregnancy, when the hormone progesterone increases the tumor's growth rate. A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ...

Headaches may be present.

The diagnosis is confirmed by testing hormone levels, and by radiographic imaging of the pituitary (for example, by CT scan or MRI). CAT apparatus in a hospital Computed axial tomography (CAT), computer-assisted tomography, computed tomography, CT, or body section roentgenography is the process of using digital processing to generate a three-dimensional image of the internals of an object from a large series of two-dimensional X-ray images taken around... The mri are a fictional alien species in the Faded Sun Trilogy of C.J. Cherryh. ...

Treatment

Treatment options depend on the type of tumor and on its size. Prolactinomas are most often treated with bromocriptine or more recently, cabergoline which, unlike bromocriptine, decreases tumor size as well as alleviates symptoms, both dopamine agonists, and followed by serial imaging to detect any increase in size. Treatment where the tumor is large can be with radiation therapy or surgery, and patients generally respond well. Efforts have been made to use a progesterone antagonist for the treatment of prolactinomas, but so far have not proved successful. Thyrotrophic adenomas respond to octreotide, a long-acting somatostatin analog, in many but not all cases according to a review of the medical literature. Unlike prolactinomas, thyrotrophic adenomas characteristically respond poorly to dopamine agonist treatment.^[1] Bromocriptine is an ergoline derivative dopamine agonist that is used in the treatment of pituitary tumors and Parkinsons disease. ... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... The antagonist is the character (or group of characters) of a story who represents the opposition against which the heroes and/or protagonists must contend. ... Somatostatin is a hormone. ...

References

1. ^  ^a  Chanson, Philippe; Weintraub, Bruce D.; and Harris, Alan G. (1993) Octreotide Therapy for Thyroid-Stimulating Hormone-Secreting Pituitary Adenomas. Annals of Internal Medicine 119 (3), 236-240.