Pituitary adenomas are benign tumors that vary greatly in size and direction of spread1,2
Constitute approximately 10% of all intracranial neoplasms
Low proliferation activity
Local invasion of bone and soft tissue is common with benign adenomas
Small tumors tend to be smooth and round; but as size increases, they often become irregular with nodules extending in various directions
Symptoms can range from a few days to more than 10 years
Etiology:
Erin
Since most pituitary tumors are benign, malignant tumors are extremely rare. Therefore, not much knowledge of the etiology exists.1 There has been an unclear speculation of a connection between prolactin secreting tumors (PRL) in women and the use of oral contreceptives.
Signs & Symptoms:
Spencer
Depending on the type of tumor (benign or malignant), or whether or not it is a functioning or non-functioning tumor, there can be various types of signs and symptoms associated with this gland.
These are the most common forms of symptoms associated with the pituitary gland:1 - Headache - Nausea - Some loss of vision - Confusion - Dizziness - Seizures
Diagnostic Procedures:
Pablo Medical tests that will help in the diagnosis of pituitary tumors include the following:
Blood/Urine: To determine a deficiency or an over production of a certain hormone.
Brain Imaging: computer tomography (CT), magnetic resonance imaging (MRI).
Physical and history.
Vision test.
Endocrine function test.
Neurological exam.
Biopsy.¹
Histology:
Becky
The glandular cells that make up the secretion of hormones consist of acidophils and basophils.
Acidophils- secretes GH (growth hormone), controls body growth; PRL (prolactin), initiates milk production.
Basophils- secretes TSH (thyroid stimulation hormone), controls thyroid gland, FSH (follicle-stimulating hormone), stimulates egg and sperm production, LH (luteinizing hormone), stimulates other sexual and reproductive activity, MSH (melanocyte-stimulating hormone), skin pigmentation, and ACTH (adenocorticotropic hormone), activity of adrenal cortex.1
Lymph node drainage:
Adam The pituitary is an endocrine gland, which are known to have abundant blood or lymphatic supplies. In the case of the pituitary, it relies on capillaries rather than lymphatic ducts as its drainage system. Through these capillaries, the various hormones that the the pituitary secretes are able to travel through the body.1
Metastatic spread:
Megan Routes of spread for pituitary cancers do not use the blood as a vehicle for metastasis. This is because pituitary adenomas are histologically benign.1 The spread occurs by local invasion and compression.1 Lateral invasion into the cavernous sinus may come with ocular dysfunction caused from the compression of cranial nerves II, IV, and VI. If metastasis has occurred, and the optic nerve is compressed, bilateral vision loss may occur, as well as headaches, increased intracranial pressure, or cerebrospinal fluid rhinorrhea (a condition where cerebrospinal fluid leaks from the sinuses).1
Grading:
Kevin T* Hardy and Vezina developed a staging system that classifies pituitary tumors into 4 grades according to extent of expansion or erosion of the sella.1Grade I and II represents enclosed adenomas
o Grade I: normal-sized sella with possible asymmetry of the floor
o Grade II: enlarged sella with an intact floor
o Grade III: localized erosion or destruction of the sellar floor
o Grade IVL diffusely eroded floor.
Grade III and IV represents invasive adenomas
Suprasellar extension requires a second type of staging.1
o Type A: tumor bulges into chiasmatic cistern
o Type B: tumor reaches floor of third ventricle
o Type C: tumor is more voluminous, with extension into third ventricle up to foramen of Monro
o Type D: tumor extends into temporal or frontal fossa
Staging:
Erin
No true staging system exists for pituitary tumors since most of them are benign.1 Once a tumor if found, tests are done to see if the tumor has spread to the brain or to other parts of the body, typically using an MRI.2 The only staging used is a grading system based on the extend of expansion or erosion of the sella turcica.
Radiation side effects:
Spencer Some of the most common side effects of radiation therapy to the pituitary gland include. 2 - Damage to the optic nerve, possibly resulting in impaired vision. - Possible damage to remaining pituitary tissue, requiring possible additional hormone balancing. - Possible damage to normal brain tissue due to the radiation beam placement on entry and exit. - May increase risk of additional malignancy or brain tumor later on in life due to the use of radiation.
Prognosis:
Pablo There is a 90% control rate currently for pituitary tumors. If the diagnosis is delayed, the tumor can grow and press on the cranial nerves, therefore causing a variety of neurological dysfunctions. The 10 year survival is between 80-94%.²
Treatments:
Becky
v Primary treatment option is prescription drugs to help maintain the tumor until next step of treatment choice is needed.
v Surgery is a treatment choice however; usually it is used with radiation therapy due to recurrence rate with surgery alone.
v Radiation Therapy is treatment of choice either post-op or for medically inoperable tumors. Conventional parallel opposed laterals with an anterior vertex port may be used. Also, IMRT (intensity-modulated radiation therapy) or SRS (stereotactic radiosurgery) may be used as treatment planning.2
TD 5/5:
Adam The TD5/5 for the pituitary gland is 4500 cGy, and the expected injury is reduced hormone production.2
References:
Megan 1.) Chao C, Perez C, Brady L. Radiation Oncology Management Decisions. 3rd ed. PA: Lippincott Williams and Wilkins; 2011: 171-177. 2.) Lenards, N. Pituitary. [PowerPoint]. La Crosse, WI: UW-L Medical Dosimetry Program; 2013. 3.) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. St. Louis, MO: Mosby Inc; 2010:652-654
9.) Adams RD, Newell T. Endocrine system tumors. In: Washington CM, Leaver D, eds. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010:643-665.
10.) Chao KSC, Perez CA, Brady LW. Management of adult central nervous system tumors. In: Chao KSC, Perez CA, Brady LW, eds. Radiation Oncology Management Decisions. Philadelphia, PA: Lippincott, Williams and Wilkins; 2011: 145-191.
11.) Pituitary Cancer: The Basics. Oncolink - Cancer Resources Web Site. http://www.oncolink.org/types/article1.cfm?id=9538&c=109. Accessed June 6, 2013. 12.) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010.
Since most pituitary tumors are benign, malignant tumors are extremely rare. Therefore, not much knowledge of the etiology exists.1 There has been an unclear speculation of a connection between prolactin secreting tumors (PRL) in women and the use of oral contreceptives.
Depending on the type of tumor (benign or malignant), or whether or not it is a functioning or non-functioning tumor, there can be various types of signs and symptoms associated with this gland.
These are the most common forms of symptoms associated with the pituitary gland:1
- Headache
- Nausea
- Some loss of vision
- Confusion
- Dizziness
- Seizures
Medical tests that will help in the diagnosis of pituitary tumors include the following:
The glandular cells that make up the secretion of hormones consist of acidophils and basophils.
The pituitary is an endocrine gland, which are known to have abundant blood or lymphatic supplies. In the case of the pituitary, it relies on capillaries rather than lymphatic ducts as its drainage system. Through these capillaries, the various hormones that the the pituitary secretes are able to travel through the body.1
Routes of spread for pituitary cancers do not use the blood as a vehicle for metastasis. This is because pituitary adenomas are histologically benign.1 The spread occurs by local invasion and compression.1 Lateral invasion into the cavernous sinus may come with ocular dysfunction caused from the compression of cranial nerves II, IV, and VI. If metastasis has occurred, and the optic nerve is compressed, bilateral vision loss may occur, as well as headaches, increased intracranial pressure, or cerebrospinal fluid rhinorrhea (a condition where cerebrospinal fluid leaks from the sinuses).1
No true staging system exists for pituitary tumors since most of them are benign.1 Once a tumor if found, tests are done to see if the tumor has spread to the brain or to other parts of the body, typically using an MRI.2 The only staging used is a grading system based on the extend of expansion or erosion of the sella turcica.
Some of the most common side effects of radiation therapy to the pituitary gland include. 2
- Damage to the optic nerve, possibly resulting in impaired vision.
- Possible damage to remaining pituitary tissue, requiring possible additional hormone balancing.
- Possible damage to normal brain tissue due to the radiation beam placement on entry and exit.
- May increase risk of additional malignancy or brain tumor later on in life due to the use of radiation.
There is a 90% control rate currently for pituitary tumors. If the diagnosis is delayed, the tumor can grow and press on the cranial nerves, therefore causing a variety of neurological dysfunctions. The 10 year survival is between 80-94%.²
v Primary treatment option is prescription drugs to help maintain the tumor until next step of treatment choice is needed.
v Surgery is a treatment choice however; usually it is used with radiation therapy due to recurrence rate with surgery alone.
v Radiation Therapy is treatment of choice either post-op or for medically inoperable tumors. Conventional parallel opposed laterals with an anterior vertex port may be used. Also, IMRT (intensity-modulated radiation therapy) or SRS (stereotactic radiosurgery) may be used as treatment planning.2
The TD5/5 for the pituitary gland is 4500 cGy, and the expected injury is reduced hormone production.2
1.) Chao C, Perez C, Brady L. Radiation Oncology Management Decisions. 3rd ed. PA: Lippincott Williams and Wilkins; 2011: 171-177.
2.) Lenards, N. Pituitary. [PowerPoint]. La Crosse, WI: UW-L Medical Dosimetry Program; 2013.
3.) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. St. Louis, MO: Mosby Inc; 2010:652-654
4.) National Cancer Institute. Pituitary Tumors Treatment. National Cancer Institue. http://www.cancer.gov/cancertopics/pdq/treatment/pituitary/Patient/page1/AllPages. Modified January 18, 2013. Accessed June 4, 2013.
5.) National Cancer Institute. National Cancer Institute Web Site. http://www.cancer.gov/cancertopics/pdq/treatment/pituitary/Patient/page1. Accessed June 3, 2013.
6.) American Cancer Society. American Cancer Society Web Site. http://www.cancer.org/cancer/pituitarytumors/detailedguide/pituitary-tumors-treating-radiaton-therapy. Accessed June 3, 2013.
7.) American Cancer Society. Web Site. http://www.cancer.org/cancer/pituitarytumors/detailedguide/pituitary-tumors-diagnosis. Accessed June 1, 2013.
8.) Cox JD, Ang KK. Radiation Oncology: Rationale, Technique, Results. 9th Ed. Philadelphia, PA. 2010.
9.) Adams RD, Newell T. Endocrine system tumors. In: Washington CM, Leaver D, eds. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010:643-665.
10.) Chao KSC, Perez CA, Brady LW. Management of adult central nervous system tumors. In: Chao KSC, Perez CA, Brady LW, eds. Radiation Oncology Management Decisions. Philadelphia, PA: Lippincott, Williams and Wilkins; 2011: 145-191.
11.) Pituitary Cancer: The Basics. Oncolink - Cancer Resources Web Site. http://www.oncolink.org/types/article1.cfm?id=9538&c=109. Accessed June 6, 2013.
12.) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010.
13.) National Cancer Institute website. Pituitary Tumors Treatment (PDQ). http://www.cancer.gov/cancertopics/pdq/treatment/pituitary/Patient/page1/AllPages/Print. Accessed June 4, 2013.