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Understanding Pituitary Tumors

The pituitary gland, located centrally at the base of the brain, is the primary hormone control center of the body. What problems can arise if the pituitary gland develops a tumor?

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A healthy pituitary gland produces several important hormones, including adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands; thyroid-stimulating hormone (TSH), which stimulates the thyroid gland; luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which affect the sex organs; growth hormone (GH), which aids in glucose metabolism and cell growth; and prolactin, which influences milk secretion.


Pituitary adenomas are among the more common benign tumors of the pituitary gland, constituting 10 to 15% of all brain tumors. Smaller tumors (less than one centimeter in diameter) are called microadenomas, while larger tumors (greater than one centimeter in diameter) are called macroadenomas. Pituitary tumors can also be classified as either functional or non-functional. Functional tumors produce large amounts of irregular hormones, whereas non-functional tumors do not produce hormones.

Symptoms of Pituitary Adenomas

  1. Overproduction of Hormones Specific symptoms depend on which type of hormone is being overproduced by the tumor. Tumors producing excess ACTH can lead to Cushing's disease, which causes symptoms like obesity, hypertension, and muscle weakness. Prolactin-secreting tumors (prolactinomas) can cause irregular menstrual periods, sexual dysfunction, and abnormal breast discharge. GH-secreting tumors can cause acromegaly, characterized by abnormal enlargement of the hands and feet and changes in facial features, such as prominent cheekbones, brow, or jaw.

  2. Pituitary Insufficiency Non-functional adenomas can also lead to hormonal issues by compressing the pituitary gland, resulting in decreased or halted hormone production.

  3. Visual Field Deficiency Larger tumors may grow upwards, extending beyond the sella turcica and compressing the optic nerve, often leading to a specific type of visual field loss known as bitemporal hemianopia.

  4. Non-specific Symptoms Occasionally, sizable pituitary adenomas can cause headaches or a sense of pressure or swelling behind the eyes. Hemorrhage within the tumor can result in severe headaches, double vision, and blurred vision.

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Diagnosis Requires At Least Two Tests

The pituitary gland is a small gland within the brain, and the causes of tumor formation are still unknown. Although genetic mutations have been identified in some patients, these mutations do not necessarily cause tumors. Additionally, pituitary tumors are usually not congenital, unrelated to heredity, and can occur at any age.


Any patient suspected of having a pituitary adenoma must undergo at least two tests. One is an MRI scan of the brain focusing on the sella turcica region, providing anatomical information to determine if the adenoma has invaded adjacent structures or compressed the optic chiasm, such as the cavernous sinus. The second test is a comprehensive endocrine blood evaluation to determine if the tumor affects hormone levels. For larger tumors, a visual acuity and visual field test are necessary to diagnose whether the tumor affects the optic nerve.

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Treatment Methods

  1. Medical Treatment: Medication is effective for pituitary adenomas that overproduce prolactin and GH. For prolactinomas, the drug bromocriptine effectively lowers blood prolactin levels and shrinks the tumor. Acromegaly caused by excessive GH production can be treated with octreotide. However, bromocriptine's effectiveness on GH-secreting tumors is generally not as high as on prolactinomas.

  2. Surgical Treatment: The standard treatment for tumors is surgical removal. The goal is to safely remove the tumor to reduce pressure on the optic nerve and eliminate hormone-overproducing tumor cells. Most pituitary surgeries do not require drilling holes in the scalp and skull. The most common surgical approach is the transsphenoidal method, where the procedure is conducted through the sphenoid sinus. A cut is made inside the nose or under the lip, and the tumor is removed from the back of the nasal area and below the sella turcica. The endoscopic transsphenoidal approach for tumor removal is becoming increasingly common.

    Sometimes, MRI imaging reveals pituitary microadenomas that only require regular monitoring of the tumor condition and patient symptoms, as not all pituitary tumor patients need treatment.

  3. Radiation Therapy: If surgery cannot remove the entire tumor, radiation therapy may be necessary to control and prevent tumor growth. Conventional radiation therapy involves directing small doses of radiation at the entire sella turcica area and surrounding pituitary tissue. This technique includes the marginal normal tissue in the treatment field. Conventional radiation therapy is delivered in small daily doses over several weeks, effectively preventing tumor growth. Although the same amount of radiation is delivered to the optic chiasm and the tumor, the risk of visual complications is very low.

    CyberKnife radiosurgery is a new option for treating pituitary adenomas, focusing radiation precisely on the tumor, minimizing radiation exposure to normal brain tissue. Data shows that radiosurgery is more effective than conventional radiation therapy in reducing abnormal hormone production and shortens the treatment period. However, radiation side effects, such as the feared risk of vision loss, are significant for tumors near the optic chiasm or hypothalamus. For high-risk patients, fractionated radiation therapy can reduce damage to critical brain structures.

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