Pituitary+Gland


 * **Epidemiolgy:** || * Pituitary adenomas are the most common cause of pituitary dysfunction in adults.
 * Malignant transformation of a pituitary tumor is exceedingly rare.
 * They are almost always benign and have a low proliferative activity.1
 * Metastatic potential is negligible.1
 * Incidental pituitary tumors are found in approximately 10% of autopsies.
 * Race **
 * No racial predilection is known.2

Sex

 * Symptomatic prolactinomas are found more frequently in women.2
 * Cushing disease also is more frequent in women (female-to-male ratio 3:1).2

Age
Chromophobe adenomas- (most common) these tumors are associated with non function. Acidophillic adenomas-(responsible for the growth hormone or prolactin) - these types of tumors are associated with Acromegaly- (which is when the pituitary gland produces excess growth hormone (hGH). Basophilic adenomas - (too much ACTH, which is a thyroid stimulating hormone).  Basophilic adenomas are associated with Cushings disease. ACTH stimulates the production and release of cortisol, a stress hormone. Too much ACTH means too much cortisol, which is normally released during stressful situations. It controls the body's use of carbohydrates, fats and protein. It also helps reduce the immune system's response to swelling (inflammation).6 || Grading of Sellar Floor Destruction  Suprasellar extension  Parasellar extension  Hypopituitarism- The tumor along with radiation destroy part of the gland leaving a smaller gland. This can result in infertility and sexual dysfunction  Second Tumor Development- the radiation received during treatments could result in the formation of a secondary tumor || 2. Pituitary Tumors. Medscape Reference. Available at: [|http://emedicine.medscape.com/article/1157189-overview#a0104]. Accessed: May 27, 2012. 3. Perez CA, Brady LA, Halpern EC, Schmidt-Ullrich RK. Principles and Practice of Radiation Oncology. 4th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2004. 4. Hoppe RT, Phillips TL, Mack III M. Leibel and Phillips Textbook of Radiation Oncology. 3rd ed. Philadelphia Pa: Elsevier Saunders; 2010. 5. Pituitary Tumors Treatment. National Cancer Institute. Available at []. Accessed May 30, 2012. 6. Perez C A, Halpern E C, Brady L W, Schmidt-Ullrich R K. //Principles and Practices of Radiation Oncology//. 4th ed. Philadelphia, PA. Lippincott Williams & Wilkins; 2008:778 -796. ||
 * Most pituitary tumors occur in young adults (30-50 years of age), but they may be seen in adolescents and elderly persons.2 ||
 * **Etiology:** || Multiple oncogene abnormalities may be involved in pituitary tumorigenesis. Otherwise, no evidence of environmental, pharmacologic, or physiologic agents as a cause for pituitary tumorigenesis.2 ||
 * **Signs & Symptoms:** || * Presentation may be due to a hormonal malfunction or local tumor growth with pressure effects.1
 * Decreased visual acuity, papilledema, opthalmoplegia, and ocular motor abnormalities.1
 * Patients may be asymptomatic, but have significant visual field defects.1
 * Bitemporal hemianopsia and superior temporal defects, homonymous hemianopsia, central scotoma, and inferior temoporal field cut
 * Endocrine abnormalities may result from hypersecretion or hyposecretion of one or more of the pituitiary hormones.1
 * Endocrine evaluation before and after therapy permits assessment of response to treatment and determines necessity for hormonal replacement therapy.1
 * Signs and symptoms can be insidious, ranging from a few days to ten years.1 ||
 * **Diagnostic Procedures:** || * CT scan, MRI, radiographs.
 * Labs (blood chemistry, testosterone or estrogen levels, 24- hour urine, high and low-dose dexamethasone suppression tests).
 * Biopsy with immunohistochemistry and light and electron microscopy.5 ||
 * **Histology:** || The three histological subtypes of the pituitary tumors are:
 * **Lymph node drainage:** || Pituitary adenomas are histologically benign and don’t spread through the lymphatics or the bloodstream. They do locally invade or compress adjacent structures. They can travel laterally into the cavernous sinus which presses on the cranial nerves III, IV and VI causing extraocular muscular dysfunction. Additionally, if the optic nerve is compressed it can lead to blindness.5 ||
 * **Metastatic spread:** || Pituitary adenomas are benign neoplasms and comprise the majority of tumors arising in the sella turcica. Thus there isn't much risk of regional or distant spread. 4 ||
 * **Grading:** || **__ Grading of Pituitary Adenomas __ 4 **
 * Intact sellar floor
 * Grade I - Sella normal or focally expanded, tumor < 10mm
 * Grade II - Sella enlarged, tumor >= 10mm
 * Sellar floor not intact
 * Grade III - Localized perforation of the sellar floor
 * Grade IV - Diffuse destruction of the sellar floor
 * Grade V - Spread via cerebrospinal fluid or blood ||
 * **Staging:** || **__ Staging of Suprasellar/Parasellar Extension __** 4
 * Type 0 - Confined within sella
 * Type A - Occupies suprasellar cistern
 * Type B - Obliteration of the recesses of the third ventricle
 * Type C - Gross displacement of the third ventricle
 * Type D - Intradural extension into anterior, middle, or posterior cranial fossa
 * Type E - Extension into or beneath cavernous sinus ||
 * **Radiation side effects:** || Fatigue- normal fatigue that accompanies all radiation treatments
 * **Prognosis:** || Several factors aid in determining prognosis including the extent of abnormalities, success of the treatment normalizing endocrine activity or relieving the effects of pressure, the morbidity that can be caused by the treatment, and how effective the treatment is at preventing a recurrence. These four factors along with the type of adenoma determine the prognosis. ||
 * **Treatments:** || In many cases radiation therapy is used in conjunctions with surgery. When treating the pituitary it is important to reduce dose to surrounding tissue as much as possible due to its location and surrounding structures. Some techniques that can be utilized are vertex fields with either posterior obliques or lateral fields. In some cases stereotactic radiosurgery (SRS) is used to deliver the dose in a tight conformal fashion as well as remove need for a larger margin for set-up error and movement between fractions. Using SRS also allows for the use of multiple ports with spreads dose out more evenly to surrounding tissues. ||
 * **TD 5/5:** || TD 5/5 dose for hypopituitarism is 40 - 45 Gy ||
 * **References:** || 1. Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 3rd edition. Philadelphia, PA: Lippincott Williams & Wilkins. 2011. 171-177.

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