Pituitary adenomas are a type of tumor that begin in the adenohypophysis. The pituitary is a gland at the base of the brain has two parts: the anterior pituitary or adenohypophysis, and neurohypophysis.
Pituitary adenomas are benign neoplasms arising in one of the five cell types that exist in the anterior pituitary. Depending upon the affected cells, the tumor manufacture a particular hormone or other type: cells producing growth hormone, prolactin-producing cells, cells producing thyroid stimulating hormone, stimulating hormone producing cells of the adrenal glands producing cells stimulating hormone ovarian cycle.But some tumors produce more of a hormone, most often the production of growth hormone and prolactin together. And other tumors that do not produce any hormones or cause the loss of manufacturing any of the pituitary hormones.
Clinical manifestations of pituitary adenoma will depend on two things: hormone-secreting tumors, the type of hormone or hormones they produce, and if you do not make hormones, symptoms resulting from growth or blockage in the manufacture of other hormones . In the case of prolactinoma (prolactin-producing tumor) milk secretion may exist outside pregnancy. In the case of growth hormone hypersecretion exist overgrowth of the individual (gigantism or acromegaly). The tumor that produces excess production of the hormone that stimulates the adrenal glands produce Cushing’s syndrome, and the tumor that produces greater amounts of thyroid stimulating hormone will cause hyperthyroidism.
The clinical evidence of tumor growth will arise from compression of adjacent structures. Thus, when the upstream growing adenoma compresses the optic chiasm, ie the combination of the optic nerves which carry impulses from the retina. So there may be characteristic symptoms such as loss of vision in the lateral regions of the visual field. At the same time, if the adenoma growth is predominantly lateral regions may affect the cranial nerves III, IV, and V. Thus symptoms may appear as drooping eyelid, paralysis of eye movements, pain and tingling in the face. If, on the other hand, adenoma growth affects the hypothalamus, symptoms may become apparent as excess food intake disorders, body temperature control, etc. and diabetes insipidus.
Tumor growth that can not produce hormones to condition growth failure of one or more hormones, giving a lack of pituitary function, partial or total (what is called pituitary insufficiency).
The suspected diagnosis begins with medical and blood tests of hormones.
The study was completed with imaging to locate and determine the extent of the adenoma and the possible involvement of adjacent structures. The best technique is magnetic resonance.
Treatment may be blocking or eliminating the tumor and the treatment of excess hormones. This can be done through three treatment modalities: medical treatment, surgery and radiotherapy.
Surgical treatment is usually performed through the nose (transphenoidal surgery), and is a fairly safe. In the case of small adenomas have high cure rate, whereas in larger tumors the cure is minor. The results after surgery are usually very fast, but may recur in subsequent years. The main disadvantage is that to remove part of the pituitary, may have a deficit then one or more pituitary hormones developed hypopituitarism.
Radiation therapy is usually effective in slowing the growth of an adenoma, although their results often take time and is not usually achieve symptom control quickly. Can be used as adjuvant after surgery.
Medical treatment is usually performed as hypersecretory predominant hormone. In the case of prolactinomas is preferred cabergoline or bromocriptine; in excess secretion of growth hormone and thyroid stimulating hormone octreotide is preferred.
The stimulating hormone-secreting tumors of the adrenal glands and the hormones produced tumors that do not respond to medication and require surgery or radiation therapy.
There are no measures to prevent the occurrence of a tumor in the pituitary But first symptoms of hormonal hypersecretion must be gone to the doctor for a proper examination.v
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