Pituitary tumors form in the pituitary gland, a pea-sized organ at the base of the brain about 2 inches straight back from the bridge of the nose. Because the pituitary gland produces hormones that affect other glands and many body functions, including growth, it is often referred to as the “master gland.” Ninety-nine percent of pituitary tumors are noncancerous (benign). However, because the pituitary gland affects important body functions, these tumors can cause serious symptoms and require specialized and often urgent treatment. At the University of Michigan’s Pituitary and Neuroendocrine Center, all patients with pituitary tumors are seen by a pituitary endocrinologist and a pituitary neurosurgeon, who are specialists with advanced training and knowledge in dysfunctions of the pituitary gland. Our specialists have vast experience in diagnosing and treating what can be a complex condition, seeing up to 400 pituitary tumor patients every year. We offer a multidisciplinary approach to care, with experts from fields such as radiation therapy, pathology and neuro-ophthalmology available to consult whenever needed.
Pituitary Types and Symptoms
The most common type of pituitary tumor is known as a pituitary adenoma. This type of pituitary tumor makes up more than 90% of all cases. If it has spread to the bones of the skull or the sinus cavity below the pituitary gland, it is known as an invasive pituitary adenoma. Cancerous pituitary tumors, known as pituitary carcinomas, are very rare.
All pituitary tumors can be divided into two basic types:
Nonfunctioning: Tumors that do not produce hormones, accounting for approximately 65 percent of pituitary tumors. Symptoms of nonfunctioning tumors include vision loss and symptoms related to loss of hormone function, such as fatigue, headache, being cold and decreased sexual function. Functioning: Tumors that produce hormones, accounting for approximately 35 percent of pituitary tumors.
The most common types of hormones made by functioning tumors are:
- Prolactin: This is the hormone that causes breast milk during and after pregnancy. These tumors are called prolactinomas. Symptoms may include lack of menstrual periods and production of breast milk in women, and decline of sexual function in males.
- Adrenocorticotropic hormone (ACTH): ACTH is the hormone that causes the adrenal glands to produce cortisol. ACTH-secreting tumors can cause Cushing’s disease, with symptoms including rapid weight gain, hypertension, diabetes and skin changes.
- Growth hormone: This is the hormone that helps control body growth. Growth hormone-secreting tumors can cause acromegaly, with symptoms including abnormal growth of the hands or feet and changes in facial appearances.
There are also two types of tumors that originate outside the pituitary gland, but may be treated similarly to pituitary tumors. Meningiomas are noncancerous tumors that develop on the protective lining of the brain or spinal cord, and craniopharyngiomas are noncancerous tumors that develop near the pituitary gland.
Diagnosing a Pituitary Tumor
Because of their complex nature, pituitary tumors can be difficult to diagnose properly. Some patients who come to U-M’s Pituitary and Neuroendocrine Center have been given wrong or uncertain diagnoses. Our specialists use detailed, sophisticated hormonal tests along with medical imaging tests, such as MRIs, to diagnose patients with suspected pituitary tumors and determine what type of tumor they have. All patients are seen at their first visit by a pituitary endocrinologist and a pituitary neurosurgeon, who will work together to ensure the best treatment available. We believe seeing both specialists at the same time reduces anxiety and uncertainty for the patient, and prevents having to go back and forth between specialists.
Pituitary Tumor Treatment
The treatment will depend on what type of pituitary tumor is identified, and if it is functioning or nonfunctioning. Treatment options include:
- Drug therapy. Some tumors, such as prolactinomas, typically respond well to drug therapy. As a rule, these medications need to be taken for life to prevent tumor regrowth. Medications may also be used as part of a treatment along with surgery, or in cases where surgery does not completely cure the patient. Hormone replacement therapy may also be given to patients who are experiencing impaired pituitary function.. At U-M, we are at the forefront of research in the development of new medications to treat pituitary tumors. Through our clinical trials, patients may have access to treatments not available elsewhere.
- Radiation therapy. Although once commonly used to treat pituitary tumor patients, radiation therapy is being used less frequently today. If a tumor does not progress or recur, most patients will not need radiation therapy. Our findings have shown that only a small number of patients will require post-surgery radiation. Those include patients with tumors that recur or cannot be controlled through surgery, and the majority of those with craniopharyngiomas.
- Surgery. Surgery is used to remove most nonfunctioning tumors. Patients with Cushing’s disease or acromegaly are also typically surgical candidates. Surgery may also be used when drug therapy is not an option. Ninety-five percent of surgeries are performed transnasally, meaning they are done through the nose with the surgeon utilizing both an endoscope and microscope. The remaining 5 percent of surgeries are performed intracranially, meaning they are done through an opening in the skull. U-M’s pituitary neurosurgeons are highly trained and experienced in both procedures and are leaders in the field of pituitary tumor surgery.
Both procedures are done under general anesthetic and require an overnight hospital stay. Risks are very low but include infection, leakage of spinal fluid and bleeding. The majority of patients recover well and can resume normal activities in two to three weeks. No matter the type of pituitary tumor you have, the specialists at U-M’s Pituitary and Neuroendocrine Center offer advanced expertise in both diagnosis and treatment of these tumors. All pituitary tumor patients are seen at the same time by a pituitary endocrinologist and a pituitary neurosurgeon, with access to multidisciplinary specialists, if needed. Together, we will work to give you the best treatment available. U-M is also at the forefront of pituitary tumor research, with clinical trials available to patients with Cushing’s disease and acromegaly who qualify.