Types of Pituitary Tumors

Most pituitary tumors can be treated. Virtually all tumors can be removed surgically or reduced in size with other means, and prognosis for patients is excellent.

Pituitary adenomas are benign (noncancerous) growths commonly found in about one percent of the population and often cause the gland to produce too much or too little of a certain hormone. 

Pituitary adenomas are classified based on their size and whether or not they produce hormones.

• Microadenomas are smaller than 1 cm (less than half an inch) in diameter.

• Macroadenomas are larger than 1 cm in diameter.

• About half of all pituitary adenomas are endocrine-active (functional) tumors that secrete hormones. They are usually found when looking for the cause of a hormonal imbalance.

• Pituitary adenomas that do not produce hormones are called endocrine-inactive or nonfunctional tumors. They are usually found incidentally, often when a brain scan is performed for another reason. They can also cause of vision even to blindness, which can be reversed by pituitary surgery in some cases.

 

Endocrine-active tumors account for about half of all pituitary adenomas and are usually found when looking for the cause of a hormonal imbalance. Excessive hormone production can have a significant impact on the body. When certain hormones are in overdrive, they can lead to serious syndromes that have far-reaching health consequences. Most pituitary adenomas secrete growth hormones, adrenocortiotropin (adrenocortiotropic hormone, ACTH), prolactin, or less often, thyroid-stimulating hormone (TSH). The symptoms of endocrine-active tumors depend on what hormones the tumor secretes.

 

Growth hormone is necessary for normal growth in children and helps adults maintain healthy bone and muscle tissue. Pituitary adenomas that cause overproduction of growth hormone in adults can lead to acromegaly, or enlarged bones in the hands, feet and face, accompanied by other symptoms:

• Shoes and rings no longer fit

• Fingers and/or toes becoming wider

• Hands feeling soft, like bread dough

• Enlarged forehead, jaw, nose, lips and/or tongue

• Spaces between teeth becoming wider

• Voice deepening in males

• Skin changes, including skin tags, oily skin and excessive sweating

• Carpal tunnel syndrome (due to enlarged wrist tissue)

• Arthritis

• Sleep apnea

• Headaches

 

Because the physical changes take place slowly, it can take years before acromegaly is diagnosed. Long-term or untreated acromegaly is a life-threatening disorder, and people age 45 and older have a death rate twice that of people without the disease, normally as a result of heart attack or stroke. Long-term or untreated acromegaly can lead to high blood pressure, heart disease, type 2 diabetes, thyroid cancer and colon polyps.

Although rare in children, pituitary tumors that increase growth hormone can lead to gigantism if the child has not reached puberty.

 

The pituitary produces ACTH, which triggers the adrenal glands, to produce cortisol. Cortisol is a body steroid that helps regulate blood pressure, cardiovascular function and the metabolism of proteins, carbohydrates and fats. It also reduces the body’s inflammatory response, helps insulin break down sugar for energy and helps the body respond to stress. 

Pituitary tumors can occur in cells that make ACTH, resulting in excessive cortisol in the body. When this occurs, it creates a collection of symptoms known as Cushing’s disease. 

Although fairly rare, Cushing’s disease affects women five times more than men, and is most common among adults 20 to 50 years old. It is also associated with high blood pressure that is often hard to control, diabetes, irritability, anxiety and depression. Left untreated, this disease is a fatal disorder.

 

Cushing’s disease is associated with a wide range of symptoms:

• Upper-body obesity with thin arms and legs

• Collection of fat between the shoulders (buffalo hump)

• Rounded face (sometimes called moon face)

• Increased fat around the neck

• Severe fatigue

• Weak muscles

• Bone pain

• Thin and fragile skin that bruises easily

• Purple marks on the abdomen, thighs, buttocks, arms and breasts

• Women grow more hair on their faces, necks, chests, abdomens and thighs

• Menstrual cycles may be irregular or stop

• Men have lower libido (sex drive) and fertility

• Thin, weakened bones resulting in rib and spine fractures from everyday activities

• Obesity and slow growth in children

• Mental changes

 

Some pituitary adenomas produce excess prolactin (hyperprolactinemia), which decreases estrogen levels in women and testosterone levels in men. This disrupts the reproductive system and can lead to infertility. The tumor’s location can impair vision, which is often the first symptom people notice. Other symptoms include low bone density, low levels of other hormones (hypopituitarism), low sex drive and headaches.

General symptoms of prolactinoma can include the following conditions:

• Low bone density

• Low levels of other hormones (hypopituitarism) due to pressure from the tumor

• Low sex drive

• Headaches

• Infertility

• Vision problems

 

Prolactinoma affects sex hormones; therefore, women and men may have different symptoms. Prolactinoma symptoms that can occur in women include the following:

• Irregular menstrual cycle or no periods at all

• Milky discharge from breasts when not pregnant or breastfeeding

• Vaginal dryness, leading to painful sex

• Excessive face and body hair

• Acne

 

In men, symptoms may include erectile dysfunction and enlarged breasts, and may not be noticed until the tumor is large and the patient begins to experience headaches or vision problems.

 

These tumors cause excessive TSH production, which causes the thyroid to produce too much thyroid hormone. TSH-secreting tumors are rare, but people who have them will have the symptoms characteristic of an overactive thyroid (hyperthyroidism):

• Unexplained weight loss

• Rapid or irregular heart beat

• Shaking or tremors

• Increased appetite

• Sweating or feeling hot

• Frequent bowel movements

• Trouble falling asleep

• Anxiety

• Enlarged thyroid (lump in the front of the neck)

 

Endocrine-inactive or nonfunctional tumors do not secrete active hormones, although they may sometimes secrete a defective hormone that has no endocrine effects. Because these types of pituitary adenomas do not alter hormone levels, they are often found during a brain scan for some other reason, or after they have grown large enough to exert pressure on surrounding tissues or structures, producing symptoms:

• Headaches that get progressively worse

• Loss in peripheral vision (the extreme left or right sides of what you see) or double vision

• Severe vision loss, including blindness

• Increased pressure in the brain

• Problems with memory, weakness or numbness if the tumors are very large and press on other areas of the brain

 

 

Pituitary carcinomas are very rare, cancerous tumors that make up just 0.2 percent of all pituitary adenomas. They are equally common in women and men, most often occurring in middle age. Symptoms often mimic those of pituitary adenomas, as most pituitary carcinomas also secrete hormones. Because they are so rare and share symptoms of pituitary adenomas, pituitary carcinomas are sometimes discovered after they have spread to other parts of the body. They can be hard to treat, and require aggressive treatment, which may include surgery, radiation and chemotherapy.

 

Rathke's cleft cysts occur during fetal development when the pituitary gland does not properly form. During normal development, the pituitary gland forms as a result of downward growth of the brain into the posterior lobe, and the upward growth of cells that become the secreting part of the gland, called the anterior lobe. There is a little pouch or cavity between the two lobes that seals by birth, and the two parts of the gland become one. When the pouch does not seal, the cells secrete a mucinous substance that causes progressive enlargement (Rathke’s cleft cysts). It is important to monitor these cysts carefully with frequent MRI brain scans to ensure they are not getting larger.

 

Craniopharyngiomas are tumors that occur near the pituitary stalk and form as result of deficiencies in normal endocrine development. They are usually benign (noncancerous) and are typically diagnosed when they grow large enough to exert pressure on the brain, optic nerve or pituitary gland, and cause the following symptoms:

• Obesity

• Delayed growth in children

• Vision problem or swollen optic nerve

• Excessive thirst and urination

 

Adamantinomatous (ordinary) craniopharyngiomas are less solid (with cysts) tumors that tend to affect children under 14 years of age. These tumors account for 5 to 10 percent of all childhood brain tumors.

 

Papillary craniopharyngiomas are more solid tumors and typically found in adults over age 45. 

Craniopharyngiomas are more common in African Americans.

 

Surgery is usually the first line of treatment, followed by radiation (in adults and children 3 years and older).