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Pituitary tumors

The pituitary is a small, bean-sized endocrine gland located at the base of the brain. Often referred to as the “master gland” of the body, it controls a system of hormones that regulate growth, metabolism, the stress response and functions of the sex organs via the thyroid gland, adrenal gland, ovaries and testes. A pituitary tumor is an abnormal growth of cells within the gland.

Most pituitary tumors are benign, grow slowly and do not spread to other parts of the body. However, as the tumor grows, it may damage the hormone-releasing cells of the pituitary, causing imbalances in the hormones it releases, including:

  • Growth hormone (GH), which increases the size of muscle and bone
  • Thyroid-stimulating hormone (THS), which stimulates the thyroid gland to release T3 and T4 to stimulate metabolism throughout the body
  • Follicle-stimulating hormone (FSH), which stimulates ovarian follicle production in women and sperm production in men
  • Luteinizing hormone (LH), which stimulates the ovaries to produce estrogen in women and stimulates sperm production in men
  • Prolactin, which stimulates breast tissue in nursing mothers to produce milk
  • Adrenocorticotropic hormone (ACTH), which causes the adrenal glands to produce important substances that have properties similar to steroids


Common Symptoms

Most pituitary tumors produce too much of one or more hormones. As a result, symptoms of one or more of the following conditions can occur:

  • Hyperthyroidism in which the thyroid gland makes too much thyroid hormone
  • Cushing’s disease, when the pituitary gland makes too much of the hormone ACTH
  • Gigantism (abnormally large growth due to an excess of growth hormone) or acromegaly (a long-term condition in which there is too much growth hormone and the body’s tissues get larger over time)


Other symptoms may include:

  • Nipple discharge
  • Breast development in men
  • Enlarged hands and feet
  • Excessive body hair
  • Facial changes
  • Low blood pressure
  • Obesity
  • Sensitivity to heat or cold


Symptoms caused by pressure from a larger pituitary tumor may include:

  • Headache
  • Lethargy
  • Nasal drainage
  • Nausea and vomiting
  • Problems with sense of smell
  • Visual changes (double vision, drooping eyelids)
  • Visual field loss


Diagnosis

Your doctor will perform a physical exam and order endocrine function tests to check levels of:

  • Cortisol
  • Follicle-stimulating hormone (FSH)
  • Insulin growth factor-1
  • Luteinizing hormone
  • Serum prolactin
  • Testosterone/estradiol
  • Thyroid hormone


Tests that help confirm the diagnosis include:

  • Formal visual field testing
  • MRI of the head


Treatment

Early diagnosis and treatment is important to a favorable outcome. Generally, treatment depends on the type of tumor, the size of the tumor, whether the tumor has invaded or pressed on surrounding structures, such as the brain and visual pathways, and the individual’s age and overall health.

Three types of treatment are used, either alone or in combination:

  • Surgical removal of the tumor
  • Radiation therapy
  • Drug therapy to shrink or destroy the tumor


Medications are also sometimes used to block the tumor from overproducing hormones. For some people, removing the tumor will also stop the pituitary’s ability to produce a specific hormone. These individuals will have to take synthetic hormones to replace the ones their pituitary gland no longer produces.

The following medications may shrink certain types of tumors:

  • Bromocriptine or cabergoline are the first-line therapy for tumors that release prolactin. They decrease prolactin levels and shrink the tumor.
  • Octreotide or pegvisomant is sometimes used for tumors that release growth hormone, especially when surgery is unlikely to result in a cure.


Source: National Institute of Neurological Disorders and Stroke


For More Information

The Pituitary Network Association

Stroke Aware
Neuroscience - In The News