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Pituitary Center

Pituitary Center2019-11-22T15:23:03+00:00

Our Program

The USC Pituitary Center at Keck Medicine of USC in Los Angeles is a unique interdisciplinary program dedicated to treating and evaluating patients with pituitary tumors and other disorders affecting the hypothalamus and pituitary region. The center’s comprehensive program is led by a team of expert fellowship-trained physicians who provide the most advanced medical and surgical treatments and collaborative long-term care for patients with complex pituitary tumors and related hormonal disorders.

The program features state-of-the-art surgical options, including endoscopic endonasal pituitary surgery and other minimally invasive options, comprehensive assessment of endocrine hormone function including pituitary hormone replacement therapy, and a complete diagnostic center with endocrine stimulation testing. Keck Medical Center of USC offers both the Gamma Knife® and TrueBeam™ advanced radiosurgery options in one location, giving us a distinct technological advantage for individualizing patient treatments.

The center introduced minimally invasive surgical techniques to the field starting nearly 40 years ago; to date we have treated more than 4,000 patients with pituitary lesions. As a leading Center of Excellence in treating patients with pituitary disorders, we are known for having the largest surgical experience of any pituitary center in Southern California.

As part of a university-based medical center, the center has access to the latest clinical trials for complex pituitary conditions, including Cushing’s disease and acromegaly, and the latest translational research with genetic tumor banking.

Our Approach

Our USC Pituitary Center physicians take a multi-disciplinary approach to patient care and academic research. We emphasize communicating with our patients, referring physicians and center team members and utilize a collaborative approach during every step of treatment, from pre-operative consultation to in-hospital care, post-operative follow-up and assessment of cure. Patients are often seen in joint consultation by a neurosurgeon and neuroendocrinologist at the initial visit, and additional members of the team are called upon to assist in the care of patients as needed, including available expertise in neuro-ophthalmology, neuro-radiology and radiation oncology. The patient’s plan of care is formulated with members of the team at weekly conferences in order to streamline patient care.

The USC Pituitary Center has a long history of innovations: Its physicians were the first in Los Angeles to perform surgery for pituitary tumors through the sphenoid bone (an area inside the skull that provides a less invasive approach for surgery), lead clinical trials using dopamine agonists (a chemical or substance that acts like another substance and therefore simulates the action) to treat prolactin-secreting pituitary tumors (tumors that secrete the hormone responsible for many essential functions, including stimulating lactation) , and introduce endoscopic techniques now used by neurosurgeons worldwide.

Our Results

  • 4,200 patients had pituitary tumors removed, one of the highest volumes of such surgeries at a single center worldwide
  • Successful treatments of all types of pituitary tumors
  • Postoperative CSF leak rate between one to two percent, compared to an average of six to seven percent (“Short-term outcome of endoscopic versus microscopic pituitary adenoma surgery: a systematic review and meta-analysis.” Source
  • Set standards for outcomes of a number of pituitary diseases, including nonfunctioning pituitary adenomas, acromegaly, Cushing’s Disease, Rathke cleft cysts, craniopharyngiomas and prolactinomas


The pituitary gland is located in the center of the skull base and is the master hormone gland responsible for secreting hormones that regulate a number of vital functions. About the size of a pea, it is an extension of the hypothalamus area of the brain. Hormones released by the pituitary include human growth hormone (HGH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), antidiuretic hormone and oxytocin.

A pituitary adenoma is typically a benign, slow growing tumor arising from cells within the pituitary gland. Some pituitary tumors result in excessive production and over-secretion of hormones, which can result in a variety of syndromes including acromegaly and Cushing’s disease. A large proportion of these tumors, however, do not produce any functional hormones, but instead grow to a size where they cause symptoms because they compress surrounding structures. For this reason, larger pituitary tumors (called macroadenomas) often present with headache, visual loss and pituitary gland dysfunction. Changes in energy level, sexual function and libido and many other symptoms may be a result of a dysfunctional pituitary gland (called hypopituitarism). Although the overwhelming majority of pituitary tumors are benign, local invasion into surrounding structures (such as bone and the dura, or covering of the brain) may pose a challenge to treating these tumors. Only small group of pituitary tumors are classified as “atypical” or “malignant.”

A number of diseases can affect the pituitary gland, including tumors, cysts, and inflammatory conditions, and can cause a range of disorders. The most common pituitary tumors treated at Keck Medicine at USC are:

Nonfunctional pituitary tumors
Non-functional pituitary tumors are the most commonly treated pituitary tumors. These can present with headaches, vision loss, and/or pituitary dysfunction. Non-functional tumors do not secrete hormones but their growth can result in various issues requiring treatment. Visit our online health library for more detailed information about pituitary tumors.

Acromegaly and childhood gigantism
Acromegaly and childhood gigantism is caused by growth hormone-secreting pituitary tumors and can result in widespread disease throughout the body, affecting the heart, lungs, joints, bones, and many other systems. Visit our online health library for more detailed information about acromegaly.

Prolactin-secreting pituitary tumors (Prolactinomas)
Prolactin-secreting pituitary tumors are the most common functional pituitary tumors (tumors that secrete extra hormones), and often present with milky breast discharge and abnormal menstrual periods in women, and loss of libido and sexual dysfunction in men. These tumors can often be treated medically without the need for surgery. Visit our online health library for more detailed information about prolactin-secreting pituitary tumors.

Cushing’s Disease
Cushing’s Disease is caused by a pituitary tumor that secretes ACTH and causes excessive cortisol levels in the body. This serious disease may manifest in a variety of conditions including hypertension, diabetes, heart disease, psychological symptoms including anxiety and depression, and changes in the skin, hair, and weight of the patient. The major goal when treating Cushing’s disease is to normalize the cortisol levels in the body. Visit our online health library for more detailed information about Cushing’s disease.

Atypical or recurrent adenomas
Atypical or recurrent pituitary adenomas are generally more aggressive and invasive tumors that often require a combination of treatments to successfully address.

Hypopituitarism may be caused by one of many conditions in the pituitary gland, or following surgical or radiation treatments for these conditions. It requires detailed testing and hormonal replacement to adequately diagnose and treat this condition. Visit our online healthy library for more detailed information about hypopituitarism.

Diabetes Insipidus and SIADH (Syndrome of Inappropriate Anti-Diuretic Hormone secretion)
Diabetes insipidus and SIADH are both conditions in which the body’s fluid and sodium content are inappropriately regulated. These conditions may be caused by a variety of pituitary conditions and require prompt attention. Visit our online health library for more detailed information about diabetes insipidus and SIADH.

Rathke Cleft Cysts
Rathke cleft cysts are fluid-filled lesions derived from embryonic tissue in the pituitary gland and may compress the pituitary gland and surrounding structures.

Craniopharyngiomas are benign, yet locally invasive tumors of the pituitary and hypothalamic region. Visit our online health library for more detailed information about craniopharyngiomas.

Meningiomas are benign tumors arising from the covering of the brain (meninges) that can compress the pituitary gland and connections to the brain, resulting in malfunction of the gland or optic nerve compression and visual loss.

A chordoma is a rare, congenital tumor that can occur along any part of the lower skull base and spine. As it grows, it can cause pressure and loss of function of nearby tissues and organs (including the pituitary gland).

Arachnoid Cyst
An arachnoid cyst is a fluid-filled sac of tissue that occurs within the arachnoid layer, a membrane covering the brain or spinal cord. They can be treated with surgical fenestration (surgically creating an opening in the surface of a structure or membrane) and drainage in the rare cases when they become symptomatic.

Treatments and Services

At the USC Pituitary Center, we offer several treatment options, including the most advanced therapies available. On your first visit, you will be introduced to our neurosurgeon (Dr. Zada) and neuroendocrinologist (Dr. Carmichael). Your multidisciplinary team will meet weekly to review your case and determine the best options of treatment. These treatment options will vary depending on the type of tumor and include:

Observation – Monitoring tumor growth and activity with annual magnetic resonance imaging (MRI), laboratory tests and visual examinations is an option for patients with small or incidental lesions and who may have other medical problems.

Medical treatment – Some tumors can be treated with medicines alone. Prolactinomas, for example, can often be treated with medications, such as bromocriptine or cabergoline. Growth hormone-secreting tumors that cause acromegaly (gigantism) can sometimes be treated with medications known as somatostatin-analogues, or a medication called pegvisomant, which blocks growth hormone action.

Surgery – For many symptom-providing tumors, surgery is the first line of treatment. Patients with nonfunctioning macroadenomas, Cushing’s Disease or acromegaly are usually good candidates for surgery. A small percentage of patients with prolactinomas may be recommended for surgery.

The typical surgical approach for removing pituitary tumors is through the nostril (endonasal) and sphenoid sinus (transsphenoidal), an air-filled region located behind your nostril.

Generally, surgery for removal of a pituitary tumor takes one to three hours and is performed under general anesthesia. No external facial incisions are made. Using an advanced endoscope that provides superior visualization, your neurosurgeon will enter the sphenoid sinus. The pituitary gland sits immediately above and behind the sphenoid sinus. Pituitary tumors are typically soft tumors and can often be removed with suction and instruments called curettes.

In many cases, your surgeon will take great care to preserve the normal pituitary gland and selectively remove the tumor in order to preserve hormone function whenever possible. About one in three patients will require a small incision in the abdomen to remove a small piece of fat, which is then used to repair any cerebrospinal fluid leakage discovered during the operation.

Patients usually spend two to three days in the hospital following the operation, when hormone levels are closely monitored. Typical home recovery time is two to three weeks.

Risks associated with transsphenoidal surgery for pituitary tumors include pituitary dysfunction, bleeding, infections, cerebrospinal fluid leakage, nasal complications, sinusitis, visual loss, and a small risk of stroke or injury to major blood vessels.

A small percentage of patients with unusually large or complex pituitary tumors will not be ideal candidates for an endonasal approach and will require a traditional craniotomy approach (through the eyebrow or top of the head) to remove the tumor.

Radiation and radiosurgery – Many types of radiation are used to treat pituitary tumors, including the Gamma Knife® and conventional external beam radiation. Radiation and radiosurgery are used to control the tumor’s growth and keep excessive hormone levels lower. In some cases, the tumor will get smaller, but this result is not typically expected. The Gamma Knife® is used for tumors located more than 3 mm from these key visual structures. Visit our online health library for more detailed information about the Gamma Knife®.

Patient Information

How are pituitary adenomas diagnosed?
During your first visit, you will meet with a team that will attempt to diagnose (or verify a diagnosis of) a pituitary tumor. The way pituitary adenomas are diagnosed depends on the type of pituitary adenoma. Hormone-producing tumors are typically diagnosed by measuring hormone levels in the blood. In Cushing’s Disease, there is an excess of the hormones ACTH and cortisol. Prolactinomas demonstrate elevated levels of the hormone prolactin. In acromegaly, levels of growth hormone (GH) and IGF-1 are elevated.

Tumors that do not secrete excess hormone (nonfunctioning macroadenoma) are often diagnosed because they cause headache, visual loss or hormonal dysfunction, and are then detected on an MRI of the brain and pituitary region.

Pituitary dysfunction (hypopituitarism) is often characterized by low levels of growth hormone, thyroid hormones, cortisol (a stress hormone) and various sex hormones. The prolactin level may also be somewhat elevated in patients with these tumors.

Finally, some pituitary adenomas will be discovered incidentally on scans obtained for other reasons. Depending on several factors including the tumor size and a patient’s visual and hormonal function, treatment may or may not be necessary.

How are pituitary tumors treated?
At the USC Pituitary Center, patients are seen in joint consultation by the neurosurgeon and neuroendocrinologist at the first visit; additional team members are asked to assist in patient care as needed. Your plan of care is formulated by team members at weekly conferences. We are known for having the most extensive surgical experience of any pituitary center in Southern California. Our treatments include:

Comprehensive diagnostic testing including access to hormonal stimulation tests
Full pituitary hormone replacement of all pituitary hormones
Medical treatment of tumors, including acromegaly, Cushing’s disease, and prolactinomas.
Access to the latest clinical trials for complex pituitary disease

Minimally invasive neurosurgical approaches
Endoscopic endonasal pituitary surgery
Minimal access “keyhole” craniotomy, including eyebrow craniotomy

We are the only center in California with access to Gamma Knife® and TrueBeam™ surgical technology.

What is my prognosis from pituitary adenoma?
A patient’s prognosis depends on tumor size, type and degree of invasion into other anatomical structures. Most patients have benign pituitary tumors that can be appropriately treated, and will lead full, productive lives. Some patients require long-term medications, repeated surgeries, or radiosurgery to keep their tumor under control. Other patients will require temporary or lifelong hormone replacement.


American Cancer Society Pituitary Tumors

Medline Plus: Pituitary Tumors

Pituitary Network Association

Pituitary Society

Clinical trials
You may have the option of taking part in clinical trials being conducted at Keck Medical Center of USC and elsewhere. While clinical trial participation does not ensure that an effective treatment will be received, participation does help provide invaluable information for future treatments, and possibly a cure in the future.

Overall physician rating

Pituitary Center Rating
4.8out of 5
405 Ratings

What are patients saying about us

  • 5
    360 Ratings
  • 4
    36 Ratings
  • 3
    3 Ratings
  • 2
    2 Ratings
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    4 Ratings
4.8out of 5(405 Ratings, 92 Comments)
Nov 30, 2021

Dr. Zada has consistently been helpful and clear about my treatment plan. Answered all questions and I never feltRushed.


Our Leadership

The USC Pituitary Center is led by John Carmichael, MD, a neuroendocrinologist, and Gabriel Zada, MD, a neurosurgeon. Both are fellowship-trained pituitary experts, and lead a team of specialists in neurosurgery, neuroendocrinology, neuroradiology, pathology, neuro-ophthalmology, radiation oncology and interventional endovascular neurosurgery in providing care for patients with pituitary disease.

Our Physicians

John David Carmichaelview profile

Practicing Locations

Keck Hospital of USC
USC Healthcare Center 2
Eric Changview profile

Practicing Locations

Keck Medicine of USC - Pasadena
USC Norris Comprehensive Cancer Center

Specializing In

Central Nervous System Tumors; Gamma Knife Radiosurgery, Spine Radiosurgery

Kyle Hurthview profile

Practicing Locations

Keck Hospital of USC
USC Norris Comprehensive Cancer Center

Specializing In

Autopsy Pathology, Neuropathology, Pathology

view profile

Practicing Locations

Keck Hospital of USC
USC Norris Comprehensive Cancer Center
USC Verdugo Hills Hospital

Specializing In

Diagnostic Radiology, Neuroradiology

Mark S. Shiroishiview profile

Practicing Locations

Keck Hospital of USC
USC Norris Comprehensive Cancer Center
USC Verdugo Hills Hospital

Specializing In

Diagnostic Radiology, Neuroradiology

Peter A. Singerview profile

Practicing Locations

Keck Hospital of USC
USC Healthcare Center 2
Bozena B. Wrobelview profile
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Practicing Locations

Keck Hospital of USC
USC Norris Comprehensive Cancer Center
Gabriel Zadaview profile

Practicing Locations

Keck Hospital of USC
USC Norris Comprehensive Cancer Center

Specializing In

Brain and Tumor Neurosurgery, Neurosurgery

Additional Team Members

Monica Chiu, RN
Emily Rorden, RN, MSN, ACNP-BC

Keck Medicine of USC
Univeristy of Southern California
Keck Medicine of USC
Keck Medicine of USC
Keck Medicine of USC is the University of Southern California’s medical enterprise, one of only two university-owned academic medical centers in the Los Angeles area.