Our 24/7 cancer helpline provides information and answers for people dealing with cancer. We can connect you with trained cancer information specialists who will answer questions about a cancer diagnosis and provide guidance and a compassionate ear.
Our highly trained specialists are available 24/7 via phone and on weekdays can assist through video calls and online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
A tumor is an abnormal growth of cells. Tumors can start nearly anywhere in the body. Tumors that start in the pituitary gland are called pituitary tumors.
To understand pituitary tumors, it helps to know something about the pituitary gland and what it does.
The pituitary is a small gland at the base of the skull, just below the brain and above the nasal passages and the fleshy back part of the roof of the mouth (known as the soft palate). The pituitary sits in a tiny bony space called the sella turcica. The nerves that connect the eyes to the brain, called the optic nerves, pass just above it.
The pituitary is connected directly to part of the brain called the hypothalamus. This provides a key link between the brain and the endocrine system, a collection of glands and organs in the body that make hormones. Hormones are substances released into the blood that control how other organs work. The hypothalamus releases hormones into tiny blood vessels connected to the pituitary gland. These then cause the pituitary to make its own hormones. The pituitary is considered the “master control gland” because it makes the hormones that control the levels of other hormones made by most of the endocrine glands in the body.
The pituitary gland has 2 parts, the anterior pituitary and the posterior pituitary. Each part has distinct functions.
Most pituitary tumors start in the larger, front part of the pituitary gland known as the anterior pituitary. This part of the gland makes several hormones:
The smaller, back part of the pituitary gland is really an extension of brain tissue from the hypothalamus. The posterior pituitary stores and releases hormones made by the hypothalamus (vasopressin and oxytocin) into the bloodstream.
Tumors rarely start in the posterior pituitary.
Almost all pituitary tumors are benign (not cancer) glandular tumors called pituitary adenomas. These tumors don’t spread to other parts of the body, like cancers can. Still, even benign pituitary tumors can cause major health problems because:
Pituitary cancers (called pituitary carcinomas) are very rare.
Pituitary adenomas are also known as pituitary neuroendocrine tumors (PitNETs). These benign tumors do not grow outside the skull. They usually stay in the sella turcica (the tiny space in the skull that the pituitary gland sits in). Sometimes they grow into the bony walls of the sella turcica and nearby tissues, like blood vessels, nerves, and sinuses. They usually don’t grow very large, but they can still have a big impact on a person’s health.
There is very little room for tumors to grow in this part of the skull. So, if the tumor gets larger than about a centimeter (about half an inch) across, it may grow upward, where it can press on and damage nearby parts of the brain and the nerves that arise from it. This can lead to problems like vision changes or headaches. (See Signs and Symptoms of Pituitary Tumors.)
Pituitary adenomas can be classified by size:
If a pituitary adenoma makes too much of a hormone, it's called a functional (or functioning) adenoma. If it doesn’t make enough hormones to cause symptoms, it's called a non-functional (or non-functioning) adenoma.
Functional adenomas: Most pituitary adenomas that cause symptoms make excess hormones:
Non-functional adenomas: These pituitary adenomas don’t make enough excess hormones to cause symptoms. Most often these are gonadotroph adenomas that don’t make enough hormones to cause any problems.
Non-functional adenomas account for about 3 in 10 of all detected pituitary tumors. By the time they are found, they usually have grown to be macroadenomas, causing symptoms because of their size as they press on nearby structures.
Cancers of the pituitary gland (known as pituitary carcinomas or metastatic PitNETs) are very rare. They can occur at any age, but most are found in older people. These cancers usually make hormones, just like many adenomas do.
Pituitary carcinomas look like pituitary adenomas under a microscope, so doctors have trouble telling them apart. In fact, the only way to tell for sure if a pituitary tumor is a carcinoma and not an adenoma is when the tumor spreads to another part of the body not near the pituitary gland. Most often, pituitary carcinomas spread to the brain, spinal cord, meninges (the covering of the brain and spinal cord), or bone around the pituitary. Rarely, these cancers spread to other organs such as the liver, heart, or lungs.
Several other types of benign and malignant (cancerous) tumors can grow in the region of the pituitary. All of these are much less common than pituitary adenomas.
Teratomas, germinomas, and choriocarcinomas are rare germ cell tumors that usually occur in children or young adults. They don’t develop from the hormone-making cells of the pituitary gland itself, but they can grow into the pituitary and damage it.
Rathke cleft cysts and gangliocytomas of the pituitary are rare tumors that are usually found in adults.
Craniopharyngiomas are slow-growing tumors that start above the pituitary gland but below the brain itself. They sometimes press on the pituitary and the hypothalamus, causing hormone problems. They're more common in children, but they can be seen in older adults. For more on these tumors, see Brain and Spinal Cord Tumors in Children.
Cancers that start in some other parts of the body (like the breast) can sometimes spread to the pituitary. These cancers are classified and treated based on where they started (their primary site) and are not thought of as pituitary tumors.
The rest of our information focuses mainly on benign pituitary tumors (pituitary adenomas).
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Asa SL, Mete O, Perry A, Osamura RY. Overview of the 2022 WHO Classification of Pituitary
Tumors. Endocr Pathol. 2022;33(1):6-26. Epub 2022 Mar 15.
Dorsey JF, Salinas RD, Dang M, et al. Chapter 63: Cancer of the central nervous system.
In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s
Clinical Oncology. 6th ed. Philadelphia, Pa. Elsevier: 2020.
Heaney AP. Pituitary carcinoma: Difficult diagnosis and treatment. J Clin Endocrinol Metab. 2011;96(12):3649–3660.
National Cancer Institute. Physician Data Query (PDQ). Pituitary Tumors Treatment. 2020. Accessed at https://www.cancer.gov/types/pituitary/hp/pituitary-treatment-pdq on July 6, 2022.
Snyder PJ. Causes, presentation, and evaluation of sellar masses. UpToDate. 2022. Accessed at
https://www.uptodate.com/contents/causes-presentation-and-evaluation-of-sellar-masses on July 6, 2022.
Snyder PJ. Clinical manifestations and diagnosis of gonadotroph and other clinically nonfunctioning pituitary adenomas. UpToDate. 2022. Accessed at https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-gonadotroph-and-other-clinically-nonfunctioning-pituitary-adenomas on July 6, 2022.
Last Revised: October 10, 2022