Pituitary Gland Tumors

Pituitary Gland Tumors

The pituitary gland is a tiny bean -shaped gland located at the base of your brain, posterior to your nose and between your ears. Its hormones help regulate important functions, such as growth, blood pressure and reproduction. Sometimes pituitary tumors can generate excess amounts of hormone and sometimes, pituitary tumors can limit the pituitary gland, causing it to produce lower levels of hormones (hypopituitarism), which usually originates in the anterior pituitary (adenohypohysis). A tumor can also compress the optic nerve — the nerve that transmits visual information from the eye. Most pituitary tumors are benign, nonspreading (adenomas). The cause of pituitary tumors remains unknown.

Signs and symptoms

Pituitary tumors that produce hormones are called functioning tumors and tumors that don't produce hormones are known as nonfunctioning pituitary tumors. Various types of functioning tumors can grow in your pituitary gland, each causing particular signs, and symptoms:

Adrenocorticotropic hormone-producing tumors. These pituitary tumors create the hormone adrenocorticotropin, which stimulates your adrenal glands to produce the hormone cortisol. When your adrenal glands make too much cortisol, a condition called Cushing's syndrome takes place. Signs and symptoms of Cushing's syndrome may consist of weight gain around your midsection and upper back, inflated facial roundness, a typical bulge on the upper part of your back, high blood pressure, muscle weakness and thinning of your skin.

Growth hormone-producing tumors. These tumors produce extra growth hormone (acromegaly), which may include coarsened facial features, enlarged hands and feet, high blood pressure and heart problems. Accelerated and extreme growth (gigantism) may occur in children.

Prolactin-producing tumors. Overproduction of prolactin (hyperprolactinemia) from a pituitary tumor (prolactinoma) can cause a reduction in normal levels of sex hormones — estrogen in women and testosterone in men.

In women, prolactinoma may cause irregular menstrual periods (oligomenorrhea), lack of menstrual periods (amenorrhea) and milky discharge from the breasts (galactorrhea).
In men, a prolactin-producing tumor may cause male hypogonadism, such as enlarged breasts (gynecomastia), erectile dysfunction (ED) or impotence, infertility, decrease in body hair, and loss of interest in sexual activity.

Thyroid-stimulating hormone-producing tumors. When a pituitary tumor overproduces thyroid-stimulating hormone (thyroxin). This is an unusual cause of hyperthyroidism, or overactive thyroid disease. Hyperthyroidism can increase the body's metabolism, causing sudden weight loss, a rapid or irregular heartbeat, and nervousness or irritability.

Functioning and nonfunctioning pituitary tumors may cause other signs and symptoms, including:
Headache
Vision changes, such as decreased peripheral vision or double vision
Seizures
Clear, watery nasal drainage
Hair loss
Cold intolerance
Constipation
Irritability
Weakness
Fatigue
Nausea
Vomiting
Low blood pressure

Risk factors
Even though pituitary tumors can happen at any age, they're most likely to occur in older people. People with a family history of multiple endocrine neoplasia type 1 (MEN 1) have an increased risk of pituitary tumors. In MEN 1, multiple tumors occur in different glands of the endocrine system.

Screening and diagnosis
Blood tests detect the overproduction or lack of hormones as a result of a pituitary tumor.
Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of the brain can identify a pituitary tumor.

Vision testing. These tests can conclude if development of a pituitary tumor has harmed the sight or peripheral vision.
Bone imaging. In children, an X-ray of the hand and wrist can determine whether bone growth is normal.

Treatment
Treatment for a pituitary tumor relies on the kind of tumor, its size, and how far it has spread into the brain. The age and general health also need to be considerations. Because pituitary tumors can cause severe problems by putting pressure on the brain, treatment often is essential. Early detection of pituitary tumors is important to effective treatment.
Doctors usually use surgery, radiation therapy, and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.

Surgery

The most common treatment for pituitary tumors is surgery. Surgery for a pituitary tumor normally is necessary if the tumor is pressing on an optic nerve, which can cause loss of vision. The effectiveness of surgery depends on the tumor type, its location, its size, and whether the tumor has spread. The two most important surgical procedures for treating pituitary tumors are:
Transsphenoidal hypophysectomy. With this method, a doctor usually can reach and remove the tumor through the nose and sinuses without an external incision, but very large tumors may be complicated to remove with this process, particularly if a tumor has occupied close to nerves or brain tissue.
Transcranial hypophysectomy. Through this procedure, the larger more difficult tumor is removed through the upper part of the skull by an incision in the scalp.

Radiation therapy

Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or as main treatment only if surgery isn't an alternative. Radiation therapy can be helpful if a tumor reoccurs after surgery and causes signs and symptoms that medications don't ease.

Types of radiation therapy include:
External beam radiation. This kind of radiation therapy delivers small amounts of radiation over a period of time. As this therapy is often efficient, it may take years to completely control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, mainly near the pituitary gland.
Gamma-knife radiosurgery. This type of radiation therapy focuses radiation beams exactly on the tumor without an incision. With gamma-knife radiosurgery, a small amount of radiation affects the healthy tissue surrounding the tumor, reducing the harm to normal tissue, but this therapy can’t be used if the tumor is close to an optic nerve or another sensitive structure.

Drug TherapyTreatment with medications (drug therapy) may help to stop excess hormone secretion and sometimes decrease certain types of pituitary tumors:
Prolactin-producing tumors (prolactinomas). The drugs bromocriptine (Parlodel) and cabergoline (Dostinex) can treat these types of tumors by reducing prolactin secretion and often decreasing the size of the tumor. These medications are often so successful in treating these kinds of tumors that surgery isn't necessary.
Growth hormone-producing tumors. Two types of medications are used for these kinds of pituitary tumors. Drugs known as somatostatin analogs (Sandostatin, others) cause a reduction in growth hormone production and may decrease the size of the tumor. Pegvisomant (Somavert) obstructs the result of excess growth hormone on the body. These drugs are helpful if surgery has been ineffective in regulating growth hormone production.
If a pituitary tumor has resulted in reduced hormone production, hormonal replacement may be necessary to sustain normal hormone levels.

Observation
In observation, regular follow-up tests are needed to monitor for evidence of progression of the pituitary tumor and medications, radiation therapy, and surgery aren't used. Observation may be the option if the tumor isn't causing any signs or symptoms.
Observation may be mainly appropriate due to age and/or poor health. Numerous people with pituitary tumors function normally without treatment and without the tumor causing other problems.

Pituitary Tumor Information from : Eighth Edition Profession Guide to Diseases by: Lippincott Williams and Wilkins and from : mayoclinic.org

Acoustic Neuroma

Acoustic neuroma

Acoustic neuroma is a noncancerous (benign) tumor that extends on a section of the eighth cranial nerve, (which runs from your brain to your inner ear) and controls equilibrium and hearing. Also known as vestibular schwannoma, acoustic neuroma is one of the most common types of brain tumors. Though, these tumors are unusual, occurring in about one person in 100,000.

Signs and symptoms

The signs and symptoms of acoustic neuroma are produced from the tumor pressing on the hearing segment of the eighth nerve. Most acoustic neuromas increase slowly, over many years to become large enough to cause signs and symptoms. Most likely observed in people between ages 30 and 60, acoustic neuromas are uncommon in children, and a higher incidence of occurring in women. In unusual cases, an acoustic neuroma may develop large enough (up to 6 centimeters) to compress on the brainstem and be critical

For some people, the tumor remains so tiny ( less than 1.5 centimeters) it never causes problems. They may need no treatment other than regular monitoring by their doctor .In unusual cases, an acoustic neuroma may develop large enough (up to 6 centimeters) to compress on the brainstem and be critical. Also, large tumors can stop cerebrospinal fluid flow which can cause increased fluid pressure in skull (hydrocephalus). If they need treatment, the choices include radiosurgery and surgical removal.

Signs and symptoms include:

* Permanent Hearing loss, typically gradual — although in some cases sudden — and occurring on only one side or more prominent on one side
* Ringing (tinnitus) in the affected ear
* Dizziness (vertigo)
* Loss of equilibrium
* Facial numbness and tingling
* Headaches
* Mental Confusion

The cause of acoustic neuromas is unknown. But, the tumors, in unusual cases, are a sign of neurofibromatosis 2, a genetic disorder that involves the development of tumors on the vestibulocochlear nerve (bilaterally).

Diagnosis

Because signs and symptoms of acoustic neuroma are likely to develop slowly and because hearing loss, tinnitus and dizziness can be signs of other middle and inner ear problems, it may be complicated for the doctor to identify the tumor in its beginning stage. Acoustic neuromas often are found during testing for other conditions.

* Scans. Magnetic resonance imaging (MRI) or computerized tomography (CT) scans of the head can provide images that confirm the presence of an acoustic neuroma.
* Hearing test (audiometry). During this test performed by a hearing specialist (audiologist), the patient wears earphones and hears sounds directed to one ear at a time. The audiologist presents a range of sounds of different tones and asks them to specify each time they hear the sound. Each tone is repeated at soft levels to find out when they can barely hear. The audiologist also will present various words to determine their hearing ability.
* Electronystagmography (ENG). This test assesses balance (vestibular) function by identifying abnormal rhythmic eye movement (nystagmus) often present with inner ear conditions. The test measures involuntary eye movements while stressing balance in various ways.
* Brainstem auditory evoked response (BAER). This test tests hearing and neurological functions. Electrodes on the scalp and earlobes capture the brain's responses to clicking sounds heard through earphones and record the responses on a graph.

Treatment

There are three choices for managing an acoustic neuroma: observation to determine whether it's growing and how fast, radiation and surgical removal.

Monitoring
If it is a small acoustic neuroma that isn't growing or is growing slowly and causes few or no signs or symptoms, the doctor may decide to monitor it, especially if in an older adult or otherwise not a good candidate for treatment.

The doctor may suggest regular imaging and hearing tests to determine whether the tumor is growing and how quickly. If the scans show the tumor is growing or if the tumor causes progressive hearing loss or other difficulties, treatment may be necessary.

Radiation
Several forms of radiation are used to treat acoustic neuromas. One, a procedure called gamma-knife radiosurgery, enables doctors to deliver radiation accurately to a tumor without making an incision. The doctor attaches a lightweight head frame to the numbed scalp. Using imaging scans, the doctor localizes the tumor and then plots where to apply the radiation beams. This procedure often is performed under local anesthesia.

The purpose of radiosurgery is to stop the growth of a small tumor. It also may be used for residual tumors, portions of a tumor that traditional brain surgery can't remove without damaging brain tissue.

It may take weeks, months, or years before the effects of radiosurgery become evident. The doctor will monitor the progress with follow-up imaging studies.

Immediate side effects of gamma-knife procedures are minimal and may include nausea, neck stiffness, and pain where the frame was attached to the scalp. Long-term risks may include facial paralysis and hearing loss.

Surgical removal
The purpose of surgery is to remove the tumor and maintain the facial nerve to prevent facial paralysis and preserve hearing. Performed under general anesthesia, this type of surgery involves removing the tumor through an incision in the skull. Recovery may take six to 12 weeks.

Risks include infection, bleeding, and reaction to the anesthesia. As with radiosurgery, there is a risk of hearing loss and facial paralysis. The patient is not likely to regain hearing lost as a result of the acoustic neuroma.

Acoustic Neuroma Information from: Eight Edition Profession Guide To Diseases by: Lippincott Williams and Wilkins and from: mayoclinic.org