Pituitary+Gland

 >General: History and Physical Examination >Special Test: Neurologic Examination (with special attention to cranial mass), test of visual field, and Funduscopic examination >Radiologic Studies: Skull X-Rays and MRI (or CT) >Laboratory Studies: Complete Blood Count, Blood Chemistry, and Urinalysis >Endocrine Evaluation: Gonadal Function Tests (follicle-stimulating hormone, luteinizing hormone, plasma estradiol, testosterone); Thyroid Function Tests (thyroxine, triiodothyronine, serum thyroid-stimulating hormone); Adrenal Function Tests (basal plasma or urinary steroids, cortisol response to insulin hypoglycemia, and plasma ACTH response to metyrapone administration) 9 || Table provided by American Cancer Society 10 || -Spread by CSF pathways may involve the supratentorial, infratentorial, or spinal compartments. In the supratentorial space, the tumour may spread to the interpeduncular fossa. Spread along the cortical hemispheric surface may lead to metastases in the frontal, temporal, parietal or occipital lobes. Spread to these. lobes seems to occur more often through CSF pathways than through the bloodstream. Two observed phenomena confirm this belief. First, the lesions tend to be subpial or close to the ventricular surface rather than deep in the white matter; second, patients with intracranial metastases often do not have evidence of systemic spread; if the dissemination were through the bloodstream, one should see metastases elsewhere. Subarachnoid spread in the infratentorial compartment leads to metastases in the cerebellopontine angle, in the ependymal lining of the fourth ventricle, and in the cerebellum. - Spread along the spinal subarachnoid space may lead to metastases in the spinal cord or cauda equina. 2  || Grade I: sella normal of focally expanded; tumor <10mm Grade II: sella enlarged; >10 mm Grade III: localized perforation of sellar floor Grade IV: diffuse perforation of sellar floor Grande V: spread by cerebrospinal fluid or blood. 1 Figure 1: Location of Pituitary with surrounding structures. 8 ||
 * ​Epidemiology: || Pituitary adenomas are the third most common primary intracranial neoplasm, following gliomas and meningiomas. 5  These tumors are conceptually different than other neoplasms. Malignant transformation of a pituitary tumor is exceedingly rare. They are almost always benign and have a low proliferative activity. Metastatic potential is negligible. 5 The highest occurrence is between 30-50 years of age. Women of child bearing age tend to be at greatest risk of tumor development. Autopsy studies reveal the prevalence of pituitary tumors to be equal between men and women. <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 80%; vertical-align: super;">5 ||
 * Etiology: || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"><span style="color: #0000ff; font-family: Georgia,serif;">Epidemiologic studies revealed no evidence of environmental, pharmacologic, or physiologic agents as a cause for pituitary tumorigenesis. <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 90%; vertical-align: super;">5 ||
 * Signs & Symptoms: || <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 120%;">Pituitary adenomas are the most common cause of pituitary dysfunction in adults. It is due to either consequencially from a malfunction of the gland or pressure from local tumor growth. A patient may not have any symptoms other than impared vision. The two most common vision problems are bitemporal hemianopic and superior temporal defects. Others include homonymous hemianapia, central scotoma, and inferior temporal field cut. Patients may also complain of decreased visual acuity, papilledema, opthalmoplegia, and occular motor abnormalities. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 96%; vertical-align: super;">9 ||
 * Diagnostic Procedures: || <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 120%;"><span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 140%;">__Diagnostic Workup for Pituitary Adenomas:__
 * Histology: || [[image:pit._histo._chartnew.jpg width="400" height="319"]]
 * Lymph Node Drainage: || The normal pituitary gland does not have any lymphatics. However, lymphatic spread of pituitary tumours can occur after the tumour has invaded the base of the skull. <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif; font-size: 80%; vertical-align: super;">2 ||
 * Metastatic Spread: || <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif; font-size: 120%;">-Spread through the venous system occurs initially through the cavernous sinus; posterior spread can then occur through the petrosal veins all the way to the jugular vein. Retrograde spread through the cortical draining veins may affect the superior sagittal sinus.
 * Grading: || __ **Grade: Relationship of Adenoma to Sella and Sphenoid Sinuses** __
 * Floor of the Sella:**
 * Sphenoid:**
 * Distant Spread:**
 * Staging: || Most tumors are benign so no true staging system exists. The use of the Hardy and Vezina's pituitary classification, classifies pituitary tumors in four grades which can be see in the above section. 3 ||
 * Radiation Side Effects: || Some side effects that may occur during or immediately after irradiation include epilation, scalp welling, and otitis (inflammation of the ear). Also irradiation-induced hypofunction of the pituitary gland commonly occurs. Growth failure with delayed bone age frequently occurs in children or young adults. Injuries to the optic nerves or chiasm are rare but can occur. Most cases reported have had either doses higher than 50 Gy or daily fractions greater than 2 Gy, or both. 4 ||
 * Prognosis: || <span style="color: #0000ff; font-family: Georgia,serif;">Prognosis is good. A study of 121 patients found that the five year recurrence rate was only 0.5%. These patients had initially been treated with surgery and radiation. The 25-30 ye3ar follow-up revealed the recurrence rate to increase to only 4.4%. <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 90%; vertical-align: super;">4 ||
 * Treatments: || <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">The goal in treating pituitary tumors is to define the extent of the tumor volume, evaluate the hormone levels to determine if their are deficits or excesses, eradicate the tumor mass, control excess secretions, and fix endocrine deficiencies.

Managing pituitary tumors is complex and should involve input from many different disciplines including neuroradiology, neuropathology, neuroophthalmology, endocrinology, neurosurgery, radiation oncology, and pathology. The appropriate treatment for each case depends on the size of the tumor and the emergent nature of reducing the side effects from the excess hormone production. Transphenoidal surgery or radiation therapy tend to give the same results for patients with microadenomas while patients with macroadenomas should have surgery first, then post-op radiation for elevated hormone levels, incomplete resection, and invasive tumors. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 80%; vertical-align: super;">6

<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Surgery

Transphenoidal microsurgery is good for removal of microadenomas but can also be used for adenomas that extend outside the sella. Contraindications to the transphenoidal approach are “dumbbell-shaped adenomas with constriction at the diaphragm sellae, lateral suprasellar extension, massive suprasellar tumor, and an incompletely pneumatized sphenoid.” Some delayed complications may arise after surgery. In patient with nonfunctioning adenomas, anterior pituitary function may be afftected. After surgery alone, big improvements in vision have been reported. The treatment of choice for large tumors is surgery followed by radiation therapy or radiosurgery. With large tumors and surgery alone, the recurrence rate is high although it may be delayed by many years. Large invasive tumors should be treated with radiation alone because complete resection most often is not possible and attempted removal is associated with high mortality and morbidity. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 80%; vertical-align: super;">

<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 106%;">Radiati<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;"> on

With pituitary tumors, treatments indications doses and outcomes vary with functioning vs. nonfunctioning tumors. Information for dosing guidelines is given in the table below: <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 80%; vertical-align: super;">6



<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 99%;">Another set of dosing guidelines, used the Radiation Oncology Center, Mallinckrodt Institute of Radiology are shown below <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 90%;">: <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 80%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;"> <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 99%; vertical-align: super;"> <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">

All diagnostic information should be used in defining the tumor volume. Treatment planning using two or three-dimensional techniques is usually used. MRI scans should be fused with the treatment planning CT when possible to provide the best images possible for tumor delineation. The tumor volume should include a margin for error in estimating the tumor volume and for daily setup error. The GTV is the pituitary adenoma, including any growth into surrounding areas. “Usually the entire contents of the sella and, if appropriate, the entire cavernous sinus are included in the clinical target volume.” A 1 to 1.5cm margin to the blocked should be adequate because pituitary adenomas are noninfiltrating tumors. “With fractionated stereotactic treatment setups, margins on the order of 7 mm give excellent dose distribution with minimal dose to the surrounding tissues.” <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">6

<span style="color: green; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Typical treatment techniques used are:
 * <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">“In general, portals 5 x 5 cm to 6 x 6 cm, or shaped fields to 5 to 6 cm in diameter, are used. Parallel opposed lateral ports are used.”
 * <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">To help obtain a more homogeneous dose distribution and decrease the dose delivered to the optic chiasm, fifteen degree wedges with the heels placed anteriorly can be used.
 * <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">When photon energies below 10MV are used, it is recommended to use a vertex field to reduce dose to the temporal lobes. A beam entering through the vertex of the head, at approximately the midline of the hairline, is directed posteriorly to pass approximately 1 cm behind the posterior clinioid process.” Even when there are higher energy photons used, the vertex field is still recommended to provide the best dose distribution.
 * <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">“The use of two fixed parallel-opposed fields yields poor isodose distributions and should be avoided.”
 * <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Various other techniques that can be used are “bilateral coaxial wedged fields plus a coronal field, moving arc fields, and 360-degree rotational fields.” <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4

<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Stereotactic

“Stereotactic radiosurgery with gamma knife delivers focused radiation from a cobalt-60 source to a pituitary tumor in a single session, with minimal radiation to the adjacent normal brain tissue.” Tumor control with stereotactic radiosurgery is near 100%.⁴ See table 1 above for doses and optic chiasm dose limits. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">6 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Illustration of a lateral field used for pituitary adenomas. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Sim film of an AP vertex field to help reduce dose to temporal lobes of the brain. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 89%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Illustration and sim film demonstrating the angle of the vertex beam. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Three portal arrangement with open vertex and two lateral 15 degree wedged fields using 4-MV. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4 <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Three portal arrangement with open vertex and two lateral 15 degree wedged fields using 18-MV. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">4

<span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">Three plan comparison of isodose curves. See text in photo for details of treatment. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 88%; vertical-align: super;">6 || <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Table 2. TD5/5 for stuctures in the treatmen<span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;"> t area. <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 90%; vertical-align: super;">7 || <span style="color: fuchsia; font-family: 'Calibri','sans-serif'; font-size: 10pt; line-height: 200%;"> 2. Elias, M. (n.d.) //<span style="font-family: 'Calibri','sans-serif';">Pituitary Adenomas //. Retrieved January 13, 2007, from CNS Clinic-Jordan website: <span style="font-family: 'Calibri','sans-serif'; font-size: 10pt; line-height: 200%;">[] 3. Washington,C.M & Leaver, D.(Eds.).(2004). //Principles and Practice of Radiation Therapy// (Second ed). Pg.640.St. Louis, Missouri; Mosby Inc. 4. Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd edition. Pg. 165-166. Philadelphia, PA: Lippincott Williams & Wilkins. 1999,2002. <span style="color: #0000ff; font-family: Georgia,serif;">157, <span style="color: #008000; font-family: 'Comic Sans MS',cursive;">160-166 <span style="color: #0000ff; font-family: Georgia,serif;">. 5. Murphy GP, Lawrence W, Lenhard RE. //American Cancer Society Textbook of Clinical Oncology// second edition.Atlanta, Georgia: The American Cancer Society, Inc. 1995; 411-414. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">6. Perez CA, Brady LW, Halperin EC, Schmidt-Ullrich RK. //Principles and Practice of Radiation Oncology.// 4th edition. Philadelphia, PA: Lippincott Williams & Wilkins. 2004: p. 844-849. 7. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 121%;">Radiation Oncology/Toxicity/Emami. Wikibooks. Available at: <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">[]. <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 121%;">Accessed: January 14, 2010. 8. Dasher, BG & Vann, AM. //Portal Design in Radiation Therapy//. 2nd edition. Philadelphia, PA: DWV Enterprises. 2006: 65. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">9. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 121%;">Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd edition. Philadelphia, PA: Lippincott Williams & Wilkins. 1999,2002; 157-159. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">10. Lenhard RE, Osteen RT, Gansler T. The American Cancer Society's Clinical Oncology. 1st edition. Atlanta, GA: The American Cancer Society, Inc. 2001: 684. ||
 * TD 5/5 || <span style="color: #008000; font-family: 'Comic Sans MS',cursive; font-size: 110%;">[[image:pituitarytd55new.jpg width="375" height="223"]]
 * References || 1.Gunderson, LL & Tepper, JE. (Eds.) //Clinical Radiation Oncology//. 2nd edition. Philadelphia, PA: Elsevier, Churchill & Livingstone. 2007: 569-570.