Pituitary Tumor

Definition of Pituitary Tumor

A pituitary tumor is an abnormal growth that develops within the pituitary gland. The pituitary is a pea-sized gland at the base of the brain. It secretes at least eight different hormones into the bloodstream. These hormones control most of the other glands in the body that secrete hormones.

What is going on in the body?

The pituitary gland has three parts or lobes.

• The anterior (front) lobe controls growth, thyroid function, and breast milk production and the menstrual cycle in women.
• The intermediate (middle) lobe controls darkening of the skin.
• The posterior (back) lobe controls urine production and uterine contractions during childbirth.

Pituitary tumors comprise about 10% of all brain tumors. They generally develop from the anterior lobe and are rarely caused by cancer. When the tumor enlarges, it generally grows upward. It can press on other structures, such as the optic nerves. The optic nerves carry visual signals, so vision is often affected.

Pituitary tumors can also interfere with:

• growth hormone
• male hormone production
• milk production

What are the signs and symptoms of the condition?

A pituitary tumor can cause symptoms that fall into two groups:

• general, which are common to all tumors regardless of cell type
• specific, which are characteristic of the cell type involved

General symptoms include:

• headache
• visual impairment, most commonly the loss of vision in the outside top quarter of the visual field in both eyes
• weakness

Depending on the cell type making up the tumor, symptoms may include:

• abnormal secretion of breast milk
• absence of menstrual periods
• appearance of purplish marks on the skin
• decreased sex drive in males
• development of a hump on the person's back, near the base of the neck
• excessive enlargement of the hands, feet, and facial features
• excessive growth
• hair loss and skin coarseness
• intolerance to cold
• rounded, "moonlike" facial features

What are the causes and risks of the condition?

The exact cause of pituitary tumors is unknown. Women face a higher risk of developing pituitary tumors than men.

What can be done to prevent the condition?

There is no known way to prevent pituitary tumors.

How is the condition diagnosed?

Diagnosis of a pituitary tumor begins with a history and physical exam. The healthcare professional may order tests, including:

• blood and urine tests to measure the levels of different hormones
• a cranial CT scan and cranial MRI scan to show the tumor itself
• a skull X-ray to show enlargement or erosion of the skull bones
• visual field testing to see if the tumor is pressing on the optic nerve

What are the long-term effects of the condition?

Pituitary tumors enlarge at varying rates. Untreated tumors may eventually lead to blindness by damaging the optic nerves. After 75% of normal pituitary cells are destroyed, all pituitary function may eventually be lost.

What are the risks to others?

Pituitary tumors are not contagious, and pose no risk to others.

What are the treatments for the condition?

Many pituitary tumors can be removed surgically. The operation usually takes place through the head for larger tumors and through the nose for smaller ones. Radiation therapy can shrink some tumors. Medicines, such as bromocriptine, can shrink certain tumors that affect breast milk production.

What are the side effects of the treatments?

Surgery can be complicated by bleeding, infection, or an allergic reaction to the anesthetic.

What happens after treatment for the condition?

Treatment, even if successful, may not correct the visual impairment. Most people will require some form of hormone replacement medicine, even after successful surgery.

How is the condition monitored?

The individual needs to make regular visits to the healthcare professional, to whom any new or worsening symptoms should be reported.