What are pituitary tumors?

What are pituitary tumors?

Pituitary tumors are tumors found in the pituitary gland, a small organ about the size of a pea in the center of the brain just above the back of the nose. The pituitary gland makes hormones that affect growth and the functions of other glands in the body. Pituitary tumors may be grouped as follows:

• Benign adenomas, which are noncancer. These grow very slowly and do not spread from the pituitary gland to other parts of the body.
• Invasive adenomas, which spread to the outer covering of the brain, bones of the skull, or the sinus cavity below the pituitary gland.
• Carcinomas, which are malignant (cancer). These are pituitary tumors that have spread far from the pituitary gland in the central nervous system (brain and spinal cord) or outside of the central nervous system.

These pituitary tumors may be either functioning or nonfunctioning. Tumors that make one or more of the pituitary hormones are called functioning tumors, while those that do not make hormones are called nonfunctioning tumors. Each type of functioning tumor causes different symptoms, depending on the type of hormone that is being made by the tumor. Symptoms may also be caused if the tumor grows large and presses on nearby parts of the brain. A doctor should be seen if there are symptoms such as these:

• Headaches.
• Trouble seeing or moving the eyes.
• Vomiting.
• Any of the symptoms caused by too many hormones, as described under the tumor types in the Stage Explanation ¹ section.

Some cancers in other parts of the body may metastasize (spread) to the pituitary gland, but these pituitary tumors usually do not cause symptoms. Breast and lung cancer are the most common types of cancer that spread to the pituitary.

If there are symptoms, a doctor may order laboratory tests to see what the hormone levels are in the blood. The doctor may also order an MRI (magnetic resonance imaging) scan, which uses magnetic waves to make a picture of the inside of the brain. Other special x-rays may also be done.

Glossary Terms

A noncancerous tumor that starts in gland-like cells of the epithelial tissue (thin layer of tissue that covers organs, glands, and other structures within the body).

Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

Cancer that begins in the skin or in tissues that line or cover internal organs.

CNS. The brain and spinal cord. Also called CNS.

A tumor that is found in endocrine tissue and makes hormones (chemicals that travel in the bloodstream and control the actions of other cells or organs).

An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.

One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.

A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

Cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types are diagnosed based on how the cells look under a microscope.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, nuclear magnetic resonance imaging, and NMRI.

A tumor that is found in endocrine tissue but that does not make extra hormones (chemicals that travel in the blood and control the actions of other cells or organs).

A part of the body that performs a specific function. For example, the heart is an organ.

The main endocrine gland. It produces hormones that control other glands and many body functions, especially growth.

A tumor that forms in the pituitary gland. The pituitary is a pea-sized organ in the center of the brain above the back of the nose. It makes hormones that affect other glands and many body functions, especially growth. Most pituitary tumors are benign (not cancer).

A column of nerve tissue that runs from the base of the skull down the back. It is surrounded by three protective membranes, and is enclosed within the vertebrae (back bones). The spinal cord and the brain make up the central nervous system, and spinal cord nerves carry most messages between the brain and the rest of the body.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

To eject some or all of the contents of the stomach through the mouth.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.