pituitary adenoma

Pituitary adenoma: description

A pituitary adenoma is a rare, benign tumor of the pituitary gland (pituitary gland) in the skull. He accounts for about 15 percent of all brain tumors. The disease can occur at any age, but is usually diagnosed between the ages of 35 and 45 years.

The pituitary adenoma grows in the so-called Turkish saddle (Sella turcica). This is a bony hollow of the anterior skull base, in which the pituitary gland lies. The optic nerves cross in the immediate vicinity. The hypothalamus, the control center of the pituitary gland, is also located here. When a pituitary tumor causes symptoms, it usually relies on the displacement of adjacent brain structures.

Forms of pituitary adenoma

The pituitary gland forms various messenger substances (hormones) with the help of various glandular cells. In principle, a pituitary adenoma can emerge from each of these different glandular cells and subsequently cause an overproduction of the respective hormone. About 60 percent of all patients have such an endocrine-active pituitary adenoma:

In about 30 percent of cases, the breast milk-promoting hormone prolactin is increasingly produced. This pituitary tumor is called prolactinoma. Somewhat less frequently, about 20 percent of the growth hormone is increasingly released. In about five percent of cases, adrenocorticotropic hormone (ACTH) is affected by overproduction. Very rarely does a pituitary adenoma affect the production of thyroid and sex hormones.

In addition to these endocrine-active tumors, there are also those that do not affect hormone production. In about 40 percent of all patients with a pituitary adenoma this endocrine remains inactive.

Pituitary adenoma: symptoms

Not infrequently, years pass before a pituitary tumor causes symptoms, because it grows very slowly. Although it is basically a benign tumor, the pituitary adenoma can cause dangerous symptoms due to its location in the skull – either because the tumor pushes on neighboring brain structures or because it disturbs the hormone metabolism.

General brain tumor symptoms such as headache, nausea, vomiting, muscle paralysis, and a hydrocephalus are most likely to occur in a large pituitary adenoma.

If the pituitary adenoma presses on the optic nerve, visual disturbances develop. Often, the outer visual fields often fail. Some sufferers look blurry or double. In a pituitary adenoma, however, such vision problems need not be continuous. They can also change and appear differently. Large tumors can even blind them. The pituitary gland can form six different hormones on corresponding signals from its superordinate center (hypothalamus). These stimulate other endocrine glands in the body (such as the thyroid or adrenals) to produce hormones in turn. This allows the hypothalamus and pituitary to regulate the secretion of various hormones in the body.

A pituitary adenoma may affect the function of the hypothalamus or pituitary gland. Then too many or too few hormones may be formed. Therefore, different complaints may occur. Although the cause of all these complaints is a pituitary adenoma, some syndromes have their own names such as prolactinoma, acromegaly and Cushing’s disease (see below).

Prolactin and sex hormones

The hormone prolactin is especially important during pregnancy and lactation. It is produced in the pituitary gland and causes the breast to produce milk. If a pituitary adenoma increasingly forms prolactin, it is called a prolactinoma. Women can then have a milk intake without pregnancy. In men with a prolactinoma, the breast grows and looks more feminine.

In addition, the female (estrogen) and male (testosterone) sex hormones may be affected by a prolactinoma or other pituitary tumor. In women, the menstrual period may be irregular or completely absent. In some, the physical pleasure (libido) subsides. Men sometimes have problems building an erection (loss of potency).

growth hormones

Not only for the growth of the body and the development of children is the growth hormone from the pituitary important. In adults, it also controls important body functions such as bone, fat and muscle metabolism. If too many growth hormones are formed by a pituitary adenoma, the body grows. In children in the growth phase one speaks of large growth (gigantism). In adults, however, most of the growth lines of the bones are already closed. With them, the growth of a growth hormone-producing pituitary adenoma is mainly increased in the hands and feet, and the facial features become coarser (acromegaly). When the jaw grows, the teeth move apart. In addition, sufferers often sweat more. Some sufferers get a hand nerve pinched (carpal tunnel syndrome) causing pain.

A pituitary adenoma can also prevent growth hormones from being released. Affected then often feel less efficient. Your fat metabolism may be disturbed, so they store more fat especially on the stomach. The blood lipid levels can also be increased. In the bones often less calcium is stored. This can reduce bone density (osteoporosis).

Adrenal cortex hormones

The pituitary gland also stimulates the adrenal glands with the control hormone adrenocorticotropic hormone (ACTH). This can release Korstisol (a stress hormone), Aldosteron (a hormone for the salt and water household) and sex hormones. If a pituitary adenoma interferes with this hormone production, complex processes in the body can be changed – especially the fat, bone, sugar, salt and fluid metabolism.

If a pituitary adenoma produces too much ACTH, Cushing’s disease develops. Symptoms include overweight (obesity), a full moon face, stretch marks on the upper body, high blood pressure, diabetes (diabetes mellitus), osteoporosis, water retention in the tissues (edema), depression and anxiety.

On the other hand, if a pituitary adenoma suppresses ACTH production, weakness, fatigue, weight loss, nausea, and vomiting occur.

thyroid hormones

A pituitary adenoma alters thyroid function in rare cases. The thyroid hormone thyroxine has a similar effect as gasoline for a car. It drives many organs and gets the body going. If it is produced in excess due to a pituitary adenoma, the heart beats faster than normal, you sweat, and the bowel works harder. It can lead to diarrhea and fever.

If, on the other hand, too few thyroid hormones are produced by a pituitary adenoma, many metabolic processes solidify. Those affected are cold, constipated, tired and without power.

Antidiuretic hormone

The antidiuretic hormone (ADH) controls the fluid balance in the body. It ensures that the urine does not lose too much water. It also affects the concentration of blood salts and blood pressure. ADH is formed by the hypothalamus, stored in the pituitary gland and released from there as needed.

A pituitary adenoma can affect ADH metabolism. If too little ADH is released, sufferers suffer from diabetes insipidus: they excrete many liters of water-clear urine. In order not to dry out, they have to drink a lot.

Pituitary adenoma: causes and risk factors

A pituitary adenoma can develop if individual glandular cells degenerate and begin to grow uncontrollably. Why this happens is not yet clear.

In some patients, a pituitary adenoma develops as part of a multiple endocrine neoplasia (MEN1). It is an inheritable condition in which several hormone glands are abnormally altered due to a genetic defect.

Pituitary adenoma: examinations and diagnosis

If there is a suspicion of a pituitary adenoma, physicians from various disciplines work together to gain certainty:

Radiologists use magnetic resonance imaging (MRI) or computed tomography (CT) to scan images from the head. Then they can see if there is actually a tumor and where exactly it is. The tumor size and possible calcification can be seen in imaging procedures. The neurologist examines the patient when muscle paralysis or headache occurs. If there are visual disturbances, an ophthalmologist is usually consulted.

Particularly important in a pituitary adenoma are the endocrinologists. You can describe the complaints of the patient and consider whether a particular hormone cycle could be impaired. In the blood, saliva and urine of patients, they can measure the individual hormone concentrations and other parameters that are important in a pituitary adenoma. This is how they find out which endocrine gland is impaired. Even after treatment, people with a pituitary adenoma are regularly examined by endocrinologists.

Often a pituitary adenoma causes very nonspecific symptoms that can be attributed to other diseases. That’s why it takes a long time before the right diagnosis can be made.

Pituitary adenoma: treatment

If a pituitary adenoma causes no symptoms, it does not necessarily have to be treated. Then it is usually checked at certain intervals with an imaging examination, if the tumor grows and then may require treatment.

Which therapy is considered for a pituitary adenoma is usually decided individually. As a rule, all physicians involved discuss with the person concerned which treatment makes the most sense. In principle, a pituitary adenoma can be operated, irradiated and treated with medication.

Pituitary adenoma: surgery

During surgery, the surgeons try to remove the pituitary adenoma as completely as possible. The special thing about this surgery is that it can often be performed over the nose. As a result, you can see no scar on the head after surgery. Larger tumors may need to be reduced in size with radiotherapy.

During surgery, surrounding structures such as vessels, nerves or the pituitary gland itself may be injured, which may require further treatment.

Examination and treatment

For more information on examinations and treatment see the article Brain Tumor.

Pituitary adenoma: drug treatment

Not all patients with a pituitary adenoma need surgery. Hormone-producing pituitary tumors such as prolactinoma can sometimes also be treated well with medication. In addition, the drug therapy is often used before the operation and when a hormone cycle after treatment is permanently damaged. ADH, thyroid, growth, sex and stress hormones can be replaced by medication deficiency. However, since the hormones are produced and released in different amounts during the course of the day and depending on the respective phase of life, this hormone replacement therapy is not easy. In order to optimally adjust the dose, different values ​​in the body must sometimes be determined at different times of the day. Even in certain situations (such as stress or infections) sufferers must take more or less medication than usual. Hormone therapy must therefore be monitored regularly by the doctor.

Pituitary adenoma: disease course and prognosis

Disease progression and prognosis in a pituitary adenoma depend very much on when it is discovered and treated. With timely therapy, the prognosis is very good. Some patients can be completely cured, others have to take hormones for life. If hormone changes persist for a long time, many different organs in the body can be damaged. Unrecognized hormone imbalances by pituitary adenoma can even be fatal.