Pituitary Tumors: What You Need to Know

What is the pituitary gland?

The pituitary [pih-TOO-ih-tare-ree] is a small endocrine [EN-doh-krin] gland at the base of the brain that controls many different organs of the body. It is called the “master gland” of the endocrine system. It controls growth, metabolism [meh-TAB-o-liz-um], reproduction, and sexual function. Hormones from the pituitary interact with target organs in the body, such as the thyroid, adrenal, and reproductive glands (ovaries in females, testes in males).

What are pituitary tumors?

The pituitary gland can develop abnormal growths (tumors) or cysts (a fluid collection). These pituitary abnormalities are quite common and as many as one in five people in the general population have a small such abnormality. In fact, pituitary tumors are the third most common primary brain tumor. Though the pituitary lies below the brain, tumors of the pituitary gland can affect the brain and the visual system as they grow larger. Pituitary tumors and cysts are rarely cancerous, but they cause problems by either putting pressure on surrounding structures (such as eye nerves) or by causing pituitary hormone abnormalities (too much or too little hormone).

How are pituitary tumors diagnosed?

Symptoms are variable from person to person, ranging from no to many symptoms. The symptoms depend on the type of tumor and whether it is associated with a hormonal abnormality. Patients often, but not always, complain of headaches. If the tumor is large it can put pressure on the eye nerves and cause visual loss, especially of the peripheral [per-IF-er-al] (side) vision. Pituitary tumors can cause too little or too much pituitary hormone to be produced and symptoms vary depending on which hormone is Pituitary Tumors: What You Need to Know by Edward. R. Laws, MD and Whitney W. Woodmansee, MD EMPOWER MAGAZINE • Vol .4, Issue 1 9 affected. Weakness and fatigue are common complaints of pituitary patients. Since pituitary tumors typically grow very slowly, it may be hard to recognize when symptoms begin. Pituitary tumors are generally diagnosed with brain imaging (MRI) to assess the structure and size of the tumor, vision testing, and hormonal laboratory testing to determine pituitary function. The diagnosis and treatment options are best determined by a team approach that involves the neurosurgeon, endocrinologist [en-doh-cri- NA-lo-jist], and ophthalmologist [ahf-thal-MOL-o-jist].

What are the most common hormonally acti ve pituitary tumors?

1. Prolactinoma [pro-lack-tin-O-ma] – These tumors secrete too much of the pituitary hormone prolactin. Prolactin is important for breast feeding. Common symptoms in women include breast discharge, irregular or absent menses, and infertility. Common symptoms in men include decreased sex drive, sexual problems, and infertility.

2. Cushing’s disease – This is a tumor that produces too much of a hormone that stimulates the adrenal gland to make excessive cortisol. Symptoms of Cushing’s disease can include weight gain (obesity), excess hair growth, hypertension, diabetes mellitus, and psychological disturbances.

3. Acromegaly [ack-ro-MEG-a-lee] – This disease is caused by a tumor that secretes too much growth hormone. Children with acromegaly develop gigantism [jy-GAN-tiz-um]. In adults, too much growth hormone causes changes in facial features, enlarged hands and feet, enlarged internal organs, hypertension, and diabetes. Acromegaly can also be associated with obstructive sleep apnea and carpal tunnel syndrome.

How are pituitary tumors treated?

Treatment options depend on the size and nature of the pituitary abnormality. Surgery is often the treatment of choice for most large tumors, except for prolactinomas, which are typically treated with medication. Modern pituitary surgery requires only a small incision, is highly effective, and relatively safe. Pituitary tumors can be removed by operating through the nasal airway using a special piece of equipment called an endoscope [EN-dohscope]. The procedure takes 3 to 4 hours. The risk is similar to operations for gallbladder disease. The operation is done under general anesthesia [an-es-THEEZ-ee-uh] and most patients do not have much pain after the procedure. Those who might need surgery include patients with very severe headaches that interfere with daily life, loss of vision from pressure on the optic nerves by the tumor, and a pituitary gland that has stopped working. Additionally, surgery may be the best way to control excessive hormone secretion. For most patients the hospital stay is 2-3 days and the time away from work is 2-4 weeks depending on the patient. Vision improves most of the time after successful surgery. Medication therapy is also available for treatment of acromegaly. Finally, radiation is sometimes required for more invasive types of pituitary tumors. Hormone replacement therapy is available for patients who have lost pituitary hormone function. Using a combination of expert medical therapy and pituitary surgery, most patients obtain excellent control of their disease and lead normal lives.

Although pituitary tumors are benign, over time they can recur. For that reason, long term scheduled follow-up visits are required. Patients should see their endocrinologists on a regular basis. He or she will monitor hormone production. Patients should also regularly see their neurosurgeon, who will review MRI scans. The rate of recurrence of pituitary tumors is generally less than 10% in 10 years, and new techniques and new forms of medical therapy will improve all the outcomes of pituitary surgery.

Dr. Laws is Director of the Pituitary/Neuroendocrine Center and Interim Director, Neuro-Oncology at Brigham and Women’s Hospital in Boston. He is also Professor of Surgery at Harvard Medical School. Dr. Laws has previously served as President of the American College of Surgeons and President of the Pituitary Society. He has authored over 500 scientific papers and book chapters, and with Andrew Kaye is co-editor of the encyclopedic volume, “Brain Tumors,” now in its third edition. In 2005, he was elected to membership in the Institute of Medicine of the National Academy of Science. He remains actively involved in surgery and in brain tumor and neuroendocrine research.

Dr. Woodmansee is Director, Clinical Neuroendocrine Program at Brigham and Women’s Hospital / Harvard Medical School, Boston, MA. She received her medical degree from the University of Colorado School of Medicine and completed her residency in Internal Medicine and Fellowship in Endocrinology at the University of Colorado Denver. Dr. Woodmansee’s clinical interests include pituitary disorders, thyroid disease and osteoporosis.