Pituitary Adenoma Fast Facts

Pituitary adenomas are tumors that grow on the pituitary gland, a small organ at the base of the brain.

Most pituitary adenomas are slow-growing and non-cancerous.

About 10% of people are thought to develop small pituitary adenomas at some point in their lives, although the tumors often produce no symptoms.

Depending on their size, location, and growth pattern, adenomas can cause a variety of symptoms.

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Most pituitary adenomas are slow-growing and non-cancerous.

What is Pituitary Adenoma?

Pituitary adenomas are tumors that affect the pituitary, a small gland in the skull underneath the brain and behind the nose. Pituitary adenomas are common, but most grow slowly and don’t spread to other parts of the body, meaning they are non-cancerous. However, larger adenomas may put pressure on the pituitary gland or surrounding tissue and cause symptoms, and some pituitary tumors produce excess hormones, leading to hormone-related symptoms.

Types of Pituitary Tumors

Pituitary tumors are categorized according to their size and type:

  • Microadenomas. These tumors are less than 10mm (about a third of an inch) in diameter and often cause no symptoms.
  • Macroadenomas. These tumors are larger than 10mm and are more likely to cause symptoms when they press on surrounding tissues.
  • Functioning Pituitary Tumors. This type of tumor produces hormones, often leading to a symptom-causing excess of the particular hormone produced by the tumor. Symptoms vary depending on which hormone the tumor produces.

Symptoms of Pituitary Tumors

Pituitary tumors cause symptoms when the growing tumor puts pressure on surrounding brain tissue, limits the normal hormone-producing function of the pituitary, or produces hormones itself.

General symptoms of pituitary tumors may include:

  • Headache
  • Nausea
  • Vomiting
  • Vision difficulties
  • Weakness
  • Chills
  • Increased urination
  • Changes in menstrual periods
  • Weight changes

Functioning pituitary tumors can produce symptoms that vary according to which hormone they produce. Types of functioning tumors and their symptoms include:

Adrenocorticotropic Hormone-Producing (ACTH) Tumors

These tumors produce a hormone that causes higher than normal cortisol levels, a condition called Cushing disease. Symptoms may include:

  • Fat accumulation in the torso and face
  • Muscle weakness in the arms and legs
  • High blood pressure and blood glucose levels
  • Skin problems, including acne, stretch marks, and bruising
  • Bone loss
  • Anxiety or depression

Growth Hormone-Producing Tumors

Symptoms of these tumors may include:

  • Increased overall growth rates in children and adolescents
  • Enlarged hands and feet
  • Changes in facial features
  • Sweating
  • Dental problems
  • Increased body hair growth
  • Elevated blood glucose levels
  • Joint pain
  • Heart problems

Prolactin-Producing Tumors

These tumors suppress the production of sex hormones, leading to symptoms that may include:

  • Changes in menstrual periods
  • Discharge from breasts and breast growth in men
  • Sexual dysfunction and decrease in sex drive
  • Low sperm count in men

Thyroid-Stimulating Hormone-Producing Tumors

These tumors may cause:

  • Sweating
  • Irritability
  • Weight loss
  • Heartbeat irregularities
  • Frequent bowel movements

What Causes Pituitary Adenoma?

Scientists don’t know what causes pituitary adenomas. The root cause of a tumor is a mutation or damage in the genes that control the growth of affected cells. The specific cause of the gene damage that triggers a tumor’s formation is usually not identifiable. In a healthy cell, these genes prevent the cell from growing or reproducing too rapidly, and the genes can also determine the cell’s normal lifespan. In a tumor’s cells, the damage to the genes causes the cells to grow and reproduce rapidly, and the cells may live longer than usual. As this rapid growth and reproduction continue, the cells grow into an abnormal mass.

Is Pituitary Adenoma Hereditary?

Most pituitary tumors do not appear to be linked to inherited traits. Instead, researchers believe most gene changes causing tumors come from external environmental factors or changes within cells that occur randomly, and with no external trigger. 

However, some pituitary tumors have been associated with inherited syndromes that produce tumors in various parts of the body, including the pituitary. These syndromes include:

  • Multiple endocrine neoplasia, type I (MEN1)
  • Multiple endocrine neoplasia, type IV (MEN4)
  • Carney complex

How Is Pituitary Adenoma Detected?

Slow-growing pituitary tumors may develop for an extended time without producing symptoms, and some tumors may never produce symptoms. Adenomas are sometimes discovered incidentally when a patient undergoes an imaging scan for another reason.

Some warning signs of a pituitary tumor may include:

  • Headaches
  • Nausea or vomiting
  • Vision problems
  • Dizziness

How Is Pituitary Adenoma Diagnosed?

Doctors may take several different diagnostic steps when they suspect a patient may have a pituitary tumor.

  • Neurological exam. A basic neurological exam will test a patient’s reflexes, balance, coordination, strength, vision, and hearing. This exam may prompt a doctor to look further for a tumor’s presence, giving a clue about the affected part of the brain.
  • Imaging. Imaging technologies are non-invasive ways to look at brain tissue and possibly detect a tumor’s presence. They may also be used to judge the tumor’s size, location, and growth. Magnetic resonance imaging (MRI) uses a strong magnetic field to produce images of the brain and central nervous system. Computerized tomography (CT) scan may also be used to look for tumors.
  • Laboratory tests. Blood tests and urine tests may be able to detect abnormal hormone levels that could be an indication of a pituitary tumor.

How Is Pituitary Adenoma Treated?

Treatment of a pituitary tumor can vary depending on the tumor’s growth rate, location, and size. In many cases, slow-growing adenomas do not require immediate treatment. In these cases, doctors will monitor the tumor with regular imaging exams and watch for the development of symptoms that might require treatment.


Surgical removal of a tumor may be necessary if it is pressing on sensitive tissue (e.g., the optic nerve) or producing hormones causing the symptoms. Some small tumors may be removed using a technique called endoscopic transnasal transsphenoidal surgery. In this procedure, a small incision is made inside the nasal cavity, and the tumor is removed via the nose and sinuses.

Larger tumors may require a procedure called a craniotomy. In this case, the surgeon makes an incision in the scalp and removes part of the skull to reach the tumor.

Radiation Therapy

Radiation therapies involve using high-energy x-rays to target and kill tumor cells directly. The radiation is typically focused on the tumor to avoid damaging healthy cells. Radiation therapy is often used when the tumor can’t be entirely removed with surgery or when the tumor is in a location that is not safely accessible. It may also be used if the tumor begins to grow again after surgery.

Side effects of radiation therapy may include headaches, memory loss, fatigue, and scalp reactions.


Medications may be used to treat functioning tumors. These drugs help block the production of excess hormones by the tumor. Some medications may also cause the tumor to shrink.

Hormone-replacement treatment may be necessary if the tumor impairs the normal function of the pituitary gland or if other treatments lead to pituitary impairment.

How Does Pituitary Adenoma Progress?

When doctors can successfully remove or treat an adenoma, most patients make a full recovery. However, some adenomas are likely to return after treatment and require additional treatment. Almost one in five non-functioning adenomas recur, and one in four prolactin-producing tumors requires intervention beyond the initial treatment.

Even with treatment, some tumors may have long-term impacts such as vision loss or ongoing hormonal imbalances.

How Is Pituitary Adenoma Prevented?

There is no known way to prevent pituitary tumors from occurring.

Pituitary Adenoma Caregiver Tips

Caring for someone with a brain tumor can be even more challenging than the already high demands of caring for someone with any other type of severe and progressive illness. Along with the physical changes that make other cancers and serious illnesses so physically and emotionally exhausting to deal with, brain tumors also often produce psychological and cognitive changes in the patient that can threaten the caregiver’s well-being.

As you care for your loved one through the progressive stages of their illness, keep these tips in mind:

  • Learn as much as possible about the potential effects of your loved one’s specific type of brain tumor. This will allow you to understand how the illness affects the sufferer’s behavior.
  • Get help from your friends and family. Caring for a brain tumor patient is a huge task, and you shouldn’t try to do it alone.
  • Take time whenever possible to step away from the patient and the illness and find time for yourself. Acknowledge that it is normal and acceptable to need occasional relief from caregiving burdens.
  • Find a support group. It can be beneficial to learn that you are not alone and that other people understand what you are going through.

Some people with pituitary tumors also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with these tumors:

Pituitary Adenoma Brain Science

The pea-sized pituitary is sometimes called the “master gland” because it helps control the action of other glands throughout the body. Glands are organs that produce chemicals called hormones which regulate bodily functions.

The pituitary works in conjunction with a part of the brain called the hypothalamus, to which the pituitary is directly connected. The hypothalamus produces several different hormones and passes them on to the pituitary, where they’re stored, released, or used to control the function of other glands. Together, the hypothalamus and pituitary monitor and regulate some of the body’s most basic and essential systems.

Some of the functions controlled or impacted by the hypothalamus and pituitary include:

  • Growth
  • Reproduction
  • Metabolism
  • Regulation of water and sodium in the body
  • Blood pressure
  • Labor, childbirth, and lactation
  • Stress responses

Pituitary Adenoma Research

Title: Prospective Study of Clinically Nonfunctioning Pituitary Adenomas (PAPS)

Stage: Recruiting

Principal investigator: Pamela U. Freda, MD

Columbia University Vagelos College of Physicians & Surgeons

New York, NY

This project is the first comprehensive prospective study of clinically non-functioning pituitary adenomas (CNFAs). Two groups of subjects will be studied: Group I will consist of 100 patients with clinically non-functioning (CNF) pituitary lesions who are asymptomatic and do not require surgery; Group II will consist of 250 patients having pituitary lesions that are symptomatic and require surgery. Patients will be followed with a series of endocrine laboratory testing, physical examinations, testing of quality of life and neurocognitive function before and serially over time, either during non-surgical management or after surgery, and in some patients before and after radiotherapy (RT). In addition, data on pituitary magnetic resonance imaging (MRI) studies and visual field testing is done over time during follow-up as part of clinical care will be collected.

PROTOCOL I: Prospective Study of the outcome of conservative non-surgical management of patients with asymptomatic, clinically non-functioning (CNF) pituitary lesions. This protocol will evaluate prospectively the outcome of non-surgical management of clinically non-functioning pituitary lesions that do not appear to need surgery as their initial therapy. The overall design consists of an initial baseline evaluation and then serial prospective follow-up studies over time for up to 5 years of follow-up. The study will evaluate laboratory testing, clinical examinations, quality of life and neurocognitive function in these patients. Data will be collected on visual fields and MRI studies of the pituitary tumor that are done prospectively as part of clinical care to evaluate these patients.

PROTOCOL II: Prospective study of the outcome of patients with symptomatic, clinically non-functioning pituitary tumors who are treated with transsphenoidal surgery and, in some cases, also radiotherapy. This protocol will evaluate prospectively the outcome of surgical management of asymptomatic clinically non-functioning pituitary lesions. The overall design consists of an initial baseline evaluation and then serial prospective follow-up studies over time with up to 5 years of follow-up. The study will evaluate laboratory testing, clinical examinations, quality of life, and neurocognitive function in these patients. Data will also be collected on visual fields and MRI studies of the pituitary tumor that are done prospectively as part of clinical care to evaluate these patients. Data will be analyzed to determine the safety of observation alone following surgery for patients who do not have a clinically significant tumor remnant, if the silent corticotroph tumor type is characterized by elevated plasma levels of ACTH or its precursor, POMC, and if it is associated with an increased tumor recurrence rate. A group of patients who are planning RT will also be studied by these same procedures before and after RT to determine if the outcomes of patients who receive RT for treatment of tumor re-growth to that of those who do not receive RT with respect to further tumor growth, endocrine or neurological dysfunction. Quality of life and neurocognitive function in patients with clinically non-functioning pituitary lesions treated with surgery alone or those who also receive radiotherapy will be prospectively assessed.


Title: Prophylactic Oral Antibiotics on Sinonasal Outcomes Following Endoscopic Transsphenoidal Surgery for Pituitary Lesions (POET)

Stage: Recruiting

Study Director: Andrew Little, MD

Barrow Brain and Spine

Phoenix, AZ  

Transsphenoidal surgery is the standard of care for most symptomatic pituitary adenomas. Since transsphenoidal surgery exploits the nasal passage to reach the sella turcica and pituitary gland, the technique causes disruption of sinonasal function and temporarily impacts sinonasal quality of life. Disrupted sinonasal function is a primary source of postoperative morbidity following transsphenoidal surgery. Common sinonasal complications include sinusitis, synechiae formation, nasal obstruction, and crusting. The development of postoperative sinusitis is specifically associated with decreased sinonasal function after surgery. Because the nasal cavity is a contaminated surgical field, practitioners routinely prescribe a course of oral postoperative antibiotics for 7-14 days (in addition to standard prophylactic perioperative intravenous antibiotics) to improve nasal functional outcomes. To date, no studies have examined whether the administration of oral antibiotics following transsphenoidal surgery improves sinonasal healing. This question has been studied in a closely-related field, functional endoscopic sinus surgery (FESS). A meta-analysis of clinical trial data obtained in FESS indicated that current literature does not support the use of oral antibiotics to reduce infection, improve symptoms scores, or improve endoscopic findings. Furthermore, there is the potential for antibiotic-related adverse events, including the emergence of bacterial resistance, Clostridium difficile infection, and allergic reactions to the medication. Despite the lack of supporting evidence in FESS, prophylactic antibiotic use for improving sinonasal healing is still common in pituitary surgery. The investigators propose to study whether prophylactic oral antibiotics following transsphenoidal surgery improve sinonasal quality of life, reduce sinusitis incidence, and promote mucosal healing following endoscopic transsphenoidal surgery.


Title: Corticotrophin-releasing Hormone (CRH) Stimulation for 18F-FDG-PET Detection of Pituitary Adenoma in Cushing Disease

Stage: Not Yet Recruiting

Principal investigator: Prashant Chittiboina, MD

National Institute of Neurological Disorders and Stroke (NINDS)

Bethesda, MD

Cushing disease is caused by a pituitary gland tumor. Patients with Cushing disease suffer obesity, diabetes, osteoporosis, weakness, and hypertension. The cure is surgery to remove the pituitary tumor. Currently, MRI is the best way to find these tumors. But not all tumors can be seen with an MRI. Researchers hope giving the hormone CRH before a PET scan can help make these tumors more visible.

Objective: To test whether giving CRH before a PET scan will help find pituitary gland tumors that might be causing Cushing disease.

Eligibility: People ages eight and older with Cushing disease that is caused by a pituitary gland tumor that cannot be reliably seen on MRI

Design: Participants will be screened with their medical history, a physical exam, an MRI, and blood tests.

Participants will have at least one hospital visit. During their time in the hospital, they will have a physical exam and a neurological exam. In addition, they will have a PET scan of the brain. A thin plastic tube will be inserted into an arm vein. A small amount of radioactive sugar and CRH will be injected through the tube. Participants will lie in a darkened room for about an hour and be asked to urinate. Then they will lie inside the scanner for about 40 minutes. After the scan, they will be asked to urinate every 2-3 hours for the rest of the day. Blood will be drawn through a needle in the arm.

Participants will have surgery to remove their tumor within three months after the scan.

Participants will then continue regular follow-up in the clinic.

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