General Questions About a Pituitary Tumor
- What causes a pituitary tumor to develop?
- Is a pituitary tumor a brain tumor?
- Is a pituitary tumor cancer?
- What are the symptoms of a pituitary tumor?
- What are other pituitary diseases that can be mistaken for pituitary
tumors?
- What is the best treatment for a pituitary tumor?
- If a tumor was successfully removed why are regular visits, blood tests
and MRIs necessary?
- If a tumor was successfully removed why are regular visits, blood tests
and MRIs necessary?
- Are all types of pituitary radiation the same?
- What are the side effects of radiation?
- Does a pituitary tumor shorten life?
1. What causes a pituitary tumor to develop?
Pituitary tumors are common. In autopsy
studies of patients who did not have known pituitary disease, as many as
26% had a small tumor (adenoma) in the gland. Molecular biology studies have
shown that a change in the DNA of pituitary cells can cause unregulated growth
of a particular cell type resulting in a pituitary tumor, called an adenoma.
There are no known environmental causes. Very uncommonly, pituitary tumors
may be inherited. In most of these patients, there is usually a family history
of other endocrine (parathyroid or pancreas) tumors or of dark skin spots
and skin and heart tumors), though in a few, there may be only pituitary
tumors.
2. Is a pituitary tumor a brain tumor?
The pituitary gland is NOT in
the brain and pituitary tissue is different from brain tissue. Since the pituitary
gland is located at the base of the brain and is connected to the brain by
a thin stalk, there is often confusion, particularly by insurance companies,
about the classification of a pituitary tumor. A pituitary tumor is NOT a brain
tumor.
3. Is a pituitary tumor cancer?
No, in over 99% of patients, this is NOT a
cancer; it is benign. Although the tumor is benign, it can cause problems because
of its size, because it causes the normal pituitary gland to become underactive
(hypopituitarism) or because of excessive hormone production by the tumor.
4. What are the symptoms of a pituitary tumor?
The symptoms of a pituitary tumor depend
on two issues: 1) the size and location of the tumor (tumor mass effects),
and 2) whether or not the tumor is producing too much or too little hormone
(endocrine function). When a tumor is large enough to compress the optic chiasm
(where the optic [eye] nerves come together) there may be loss of vision, particularly
peripheral vision. Very occasionally tumors may cause double vision. Headache
may also occur; the type of headache varies from patient to patient. Headache
may occur with a large or a small tumor.
Some tumors overproduce hormones. The most common of these is a prolactin
producing tumor (prolactinoma), followed in frequency by growth hormone producing
tumors (acromegaly) and the by ACTH tumors (Cushing’s disease) and rare
TSH producing tumors. The overproduction of these hormones causes specific
problems (see below and refer to sections on acromegaly and prolactinoma and
any articles on these tumors). A tumor may also interfere with normal pituitary
function and cause hypothyroidism (low thyroid hormone level), adrenal insufficiency
(low cortisol level), hypogonadism (loss of sexual function in men, loss of
menstrual periods or fertility problems in women). Very rarely, a pituitary
tumor causes diabetes insipidus, which results in frequent urination and excessive
thirst. Diabetes insipidus is not high blood sugar levels; it is a problem
with the ability of the kidney to retain fluid because of a deficiency of the
pituitary hormone, vasopressin (also called antidiuretic hormone). When related
to a pituitary tumor diabetes insipidus comes on after an operation to remove
the pituitary tumor. Most often diabetes insipidus is related to other another
sort of tumor (craniopharyngioma).
Specific types of tumors cause various
symptoms and changes in body function.
Prolactinoma: most commonly causes loss of sexual function and infertility
in men. Men may also have a breast discharge that looks like milk or occasionally
enlargement of the breasts. In women of reproductive age a prolactin-producing
tumor may cause milk in the breasts, a change in menstrual periods or loss
of menses or infertility. Women who have gone through menopause do not have
a change in menstrual periods to signal the problem; in this situation, headache
and loss of vision may be the first indicator of a prolactinoma. There can
sometimes be impairment of pituitary function leading to growth hormone deficiency,
hypothyroidism and adrenal insufficiency as well as the sexual dysfunction
referred to above.
More information about a Prolactinoma...
Acromegaly: Enlargement of the hands and feet and coarsening of
facial features and excessive sweating are the most common features of excessive
growth hormone production. Other problems that occur include joint pains and
arthritis, sleep apnea (excessive snoring, stopping breathing during sleep
and fatigue during waking hours), hypertension, diabetes mellitus (high blood
sugar), colon polyps, change in teeth spacing, oily skin and acne. These tumors
can also cause tumor mass effect and cause symptoms due to underproduction
of hormones (hypothyroidism, adrenal insufficiency, impaired sexual function).
Yes, the same tumor that overproduces one hormone may under produce others.
Both of these can cause symptoms.
More information about Acromegaly...
Cushing’s Disease : The term “Cushing’s Disease” refers
to the overproduction of cortisol by the adrenal glands caused by a pituitary
tumor producing an excessive amount of the pituitary hormone, ACTH. Dr. Harvey
Cushing, a neurosurgeon, first described this condition in the 1920s. Excessive
cortisol production causes weight gain (particularly in the abdomen and neck),
loss of muscle mass (legs, arms) and muscle weakness, depression, difficulty
with concentration and memory, sleep disturbance, irritability, thinning of
the skin with easy bruising, hypertension, diabetes mellitus, loss of bone
mass (osteoporosis) with a risk for bone fractures and weakening of the immune
system with a higher risk of developing infections.
More information about Cushing's Disease...
Thyroid stimulating hormone (TSH) Secreting Tumor : This is the
least common type of hormone producing pituitary tumor. Excessive TSH stimulates
the thyroid gland to enlarge (goiter) and also produce an excessive amount
of thyroid hormone (hyperthyroidism). This kind of hyperthyroidism is caused
by a pituitary tumor overproducing TSH (this is in contrast to the much more
common type of hyperthyroidism (Grave’s disease) in which the problem
is in the thyroid gland itself). In the latter the TSH is unmeasurably low
in contrast to the TSH secreting tumor in which TSH is measurable or high.
Symptoms of hyperthyroidism are similar in both kinds of hyperthyroidism and
include weight loss, nervousness, rapid heartbeat, difficulty sleeping, frequent
bowel movements and in women, less menstrual flow or loss of menstrual periods.
As with other functioning pituitary tumors these can also cause symptoms due
to the tumor size.
Non Secretory Tumor : This refers to a tumor that does not produce
an excessive amount of a pituitary hormone that can be measured in a blood
test. This type of tumor is usually discovered when patients develop visual
field problems due to the size of the tumor. This type of tumor is usually
detected after it has become large, causing loss of vision and/or headache.
Frequently as these tumors get bigger the patients have a higher incidence
of reduced pituitary function or hypopituitarism, most commonly in the form
of sexual dysfunction in men and loss of regular menses and infertility in
premenopausal women. Hypothyroidism (low thyroid hormone level) or adrenal
insufficiency (low cortisol level) may occur due to partial or complete destruction
of the normal cells of the pituitary gland. (See section on hypopituitarism
for discussion).
Craniopharyngioma/Rathke’s Cleft Cyst : These tumors are congenital
- a defect in the development of the pituitary gland which begins during fetal
(in the womb) development. The beginnings of the tumor are present at birth
but may not cause a problem until childhood or in adulthood until its size
or relationship to important structures in that part of the head causes a problem.
In fact, these tumors and cysts may never cause a problem. They are not, however,
pituitary tumors. This is not a malignant (cancerous) tumor but it often interferes
with normal pituitary function causing hypopituitarism (loss of pituitary function)
or headache or loss of vision. This type of tumor commonly causes diabetes
insipidus, frequent urination and excessive thirst (not diabetes or high blood
sugar).
5. What are other pituitary diseases that can be mistaken for pituitary tumors?
Pituitary Cyst : Any endocrine gland may develop a cyst. This occurs
commonly in the ovaries and thyroid gland; a cyst in the pituitary gland is
benign (not cancer). Many pituitary cysts cause no symptoms and don’t
grow or enlarge. Only when they do, do they become symptomatic. They can cause
headache and/or rarely interfere with normal pituitary function. If the cyst
is large, loss of vision may occur. The treatment for this problem depends
upon the size of the cyst and its proximity to the optic chiasm. Often no treatment
is necessary, but when necessary it is removed by surgery. There are no medical
treatments for this problem.
Inflammatory Problems: A number of inflammatory problems can lead
to either enlargement of the pituitary gland or infiltration into the pituitary
or the pituitary stalk or the gland above the pituitary (Hypothalamus).
Lymphocytic hypophysitis is an inflammatory process (rather than a tumor)
that can enlarge the pituitary gland and cause pituitary hormone insufficiency.
It occurs mostly in women and is often related to a pregnancy. The symptoms
can be profound. They include weakness, extreme fatigue, weight loss, and nausea
to name a few. The latter symptoms are due to ACTH deficiency, which in turn
causes adrenal gland insufficiency. Hypothyroid symptoms also occur and menstrual
periods may be interfered with. Sometimes it is not possible to differentiate
between hypophysitis and a pituitary tumor on MRI. The pituitary gland can
enlarge to cause visual problems and severe headaches. When suspected some
endocrinologists have treated these women with cortisone and in some patients
the apparent tumor shrinks. Occasionally, there is spontaneous return of normal
pituitary function.
Sarcoidosis is an inflammatory disease that usually affects the lungs. Granulomas
are inflammatory deposits that have a particular appearance under the microscope.
Sarcoidosis can also affect the pituitary gland and hypothalamus. This disease
can cause Diabetes Insipidus because it can affect sensitive areas of the pituitary
stalk or hypothalamus that control production of the hormone, vasopressin.
It can also cause sexual dysfunction or loss of menstruation, hypothyroidism,
adrenal insufficiency, or growth hormone deficiency due to actions of the granulomas
either in the hypothalamus or pituitary.
Histiocytosis and Eosinophilic Granuloma are rare diseases that can affect
the pituitary gland and hypothalamus. They have effects elsewhere in the body,
as well. As with sarcoidosis, Diabetes Insipidus is common as is pituitary
insufficiency. The disorders themselves are generally treated by specialists
for these diseases, while the pituitary issues are managed by neuroendocrinologists.
Pituitary Apoplexy: Pituitary apoplexy is a hemorrhagic disorder of the pituitary.
It generally happens in people with pituitary adenomas. It is heralded by a
severe headache often together with visual problems. The latter can be double
vision or loss of visual fields. Although apoplexy can occur with any sort
of pituitary tumor it happens most commonly in non-functioning ones. This is
especially true in individuals who were not aware that they had pituitary tumors.
A drop in blood pressure can sometimes precede apoplexy. Pituitary apoplexy
is a medical emergency. Anyone who develops such symptoms as described above
should seek immediate medical attention
6. What is the best treatment for a pituitary tumor?
Pituitary tumors are diagnosed by signs and symptoms, blood tests and X-rays.
Depending on the type, size, location, and symptoms, clinical decision must
be made as to whether any therapy is necessary and, if so, whether medical,
surgical, and radiation therapy alone or in combination are required. In some
patients, immediate therapy may not be indicated, in which case it is important
to monitor changes in signs and symptoms, blood tests, and X-rays over time.
The best treatment depends on the type of pituitary tumor. Prolactin
producing tumors are most successfully treated with medical therapy (pills).
In over 90% of patients, medical therapy (pills) reduces tumor size and blood
prolactin levels. In approximately 8-10% of patients, medical treatment is
not adequately effective and surgery, and rarely, radiation therapy, may be
necessary.
The best treatment for other types of pituitary tumors, when surgical
treatment is required, is removal of the tumor by an experienced neurosurgeon
who performs pituitary surgery frequently. Although most neurosurgeons have
some experience with pituitary surgery, only a few have devoted their career
to pituitary surgery and have the “best” records of success.
7. If a tumor was successfully removed why are regular visits,
blood tests and MRIs necessary?
A minority of patients with pituitary tumors will have a recurrence of the
tumor after the initial surgery. Even in the best surgical hands, a significant
minority of patients will have a tumor recurrence within 10 years and many
will require additional treatment (medical, surgery, pituitary radiation).
Since it is not possible to predict which patient’s tumor will recur,
all patients need regular medical follow up. Additionally, a tumor may recur
20 years or more after the original treatment. If the tumor was producing a
hormone that caused particular symptoms (Cushing’s, Acromegaly, prolactin
tumor), the patient is usually the first to recognize this. Measurement of
the appropriate hormone level in blood and/or urine is the most accurate method
of determining if the tumor has recurred. Non secretory tumors do not produce
an excessive hormone that can be measured in the blood or urine and the MRI
scan is the best method to follow this condition. In addition, periodic test
of normal pituitary function are required in patients with non hormone-secreting
tumors as hypopituitarism may be the first sign of tumor regrowth. Furthermore,
patients receiving hormone replacement need to be monitored at regular intervals
for adequacy of treatment and to learn of the availability of newer forms of
therapy.
8. Is radiation necessary in all patients? Who should have radiation
treatment to the pituitary?
Radiation to the pituitary is not the first line of treatment for most
pituitary tumors. It does not produce an immediate effect to lower excessive
hormone production or shrink the tumor. Radiation is used when there is significant
tumor remaining after surgery, there are no effective medical therapies for
the tumor, or when surgery cannot be performed. Pituitary radiation may take
several years to be effective. For example, in patients with acromegaly (excessive
growth hormone production), growth hormone levels may remain elevated for 10
to 20 years after conventional radiation.
9. Are all types of pituitary radiation the same?
No. There are different methods of delivering radiation to the pituitary
gland. Conventional (fractionated) radiation refers to delivery of a small
amount of radiation every day for 4 to 5 weeks. Stereotactic radiation refers
to delivery of a precisely focused beam of radiation to the remaining tumor,
usually as one treatment (for example, the Gamma Knife, LINEAC, proton beam).
The decision as to which type of radiation to administer must be made only
after a careful review of the MRI scan to assess the size and location of the
residual tumor. A large tumor that is near the optic chiasm (eye nerves) is
not suitable for stereotactic radiation because of the intensity (radiation
dose) of the single treatment and risk of damage to vision. Stereotactic radiation
is reserved for residual tumor that is not near the optic chiasm. Surgery is
sometimes needed to remove the portion of the tumor that is near the optic
chiasm so that more effective radiation therapy can be given.
10. What are the side effects of radiation?
The most common side effect is loss of normal pituitary function. This may
occur within a year or many years after treatment. One study reported that
50% of patients treated with conventional radiation developed deficiency of
one or more pituitary hormones within 2 years of treatment. Although development
of a pituitary hormone deficiency is not desirable, hormone replacement therapy
is available. Every patient treated with radiation, which affects the pituitary
or hypothalamus is at risk for the development of loss of pituitary function.
Therefore, periodic blood tests are required. An uncommon side effect is damage
to vision. In small number of patients, another type tumor, which may be malignant,
may develop in the area where radiation was given. Patients receiving conventional
radiation may also be at increased for stroke. The risk associated with newer
forms of radiation is not yet known. These risks must be weighed against the
risk of tumor re-growth. Hair loss does not usually occur.
11. Does a pituitary tumor shorten life?
Having a pituitary tumor should not shorten life if it is properly
treated and if the patient receives appropriate hormone replacement(s). In
large population studies, it appears that patients who had conventional, radiation
for pituitary tumors had an increased mortality (death) risk because of cerebrovascular
disease (stroke).
Pituitary hormone deficiency requires hormone(s) replacement. All medications
must be taken as directed. Additionally, there is a need for regular medical
care and monitoring of medical treatments. Most patients who have had a pituitary
tumor engage in normal work and social activities. If a patient requires steroid
(cortisol) replacement, a Medical alert bracelet or necklace should be worn
at all times. Another illness such as the flu, pneumonia or an accident requires
an increase in the steroid dose. If the patient is brought to the hospital
and unable to give the medical history, the physicians will have no way of
knowing that additional steroid is necessary. With attention to these important
details, a patient with a pituitary tumor should have a full and productive
life.
Patients with uncontrolled Acromegaly (growth hormone producing
tumor) or Cushing’s disease (excessive cortisol production)
do have an increased risk of dying earlier than expected and for having complications
of the hormone excess. Lowering of the excessive hormone level to normal reduces
this risk. Complications associated with pituitary tumors include:
Acromegaly: heart failure, high blood pressure, abnormal lipids
(cholesterol), diabetes, snoring and other sleep-related breathing problems,
joint disease, loss of reproductive function, infertility, colon polyps (benign
growths) and possibly color cancer.
Cushing’s disease: heart disease, abnormal lipids, diabetes,
high blood pressure, osteoporosis and bone fractures, depression and suicide
risk, memory loss, muscle weakness, reproductive disorders, infertility, and
susceptibility to infection.
Prolactinoma : high prolactin is not known to shorten life; however
loss of normal testosterone production in men causes osteoporosis and increases
the risk for bone fractures. This also occurs in women who have loss of regular
menstrual cycles. Non-functioning adenoma, Craniopharyngioma, Rathke’s
Cleft cyst, pituitary cyst: There is no known risk of premature death
as long as appropriate hormone replacement(s) are taken. Complications are
related to the adequacy of hormone replacement(s).
